Crotalaria juncea L.), wild beans from Ceará , Guandú ‘BRS mandarin’ [Cajanus cajan (L.) Millsp.], millet ‘BR05’ [Pennisetum glaucum (L.) R.Br.] and sorghum ‘BR 304’ [Sorghum bicolor (L.) Moench]. The absolute control of the experiment was the treatment without the use of cover crops, that is, the vegetation of spontaneous occurrence in the area. The experimental design was randomized blocks in subplots with three replications. Spore density, mycorrhizal colonization rate, easily extractable glomalin, and species present in the rhizosphere of the cover crops were determined. No differences were found in the diversity of mycorrhizal fungi associated with the different cover crops studied or in the values of spore density, root colonization, or glomalin content. Nitrogen application did not influence the mycorrhizal activity in the investigated cover crops. The most frequent species associated with cover crops were Scutellospora pellucida and Scutellospora persica in C. juncea; Gigaspora sp. on Sorghum; Glomus macrocarpum in Guandu; G. macrocarpum and Glomus clavisporum in millet; and Glomus microaggregatum and Glomus tortuosum in Spontaneous Vegetation.This study aimed to evaluate the occurrence of mycorrhizal fungi and glomalin content in soil under different cover crops with and without the application of nitrogen in the cover. The following cover plants were used: Crotalaria juncea ( Conservation cultivation systems, such as no-tillage, are at the forefront of sustainable soil management and water resources . One of Cover plants are responsible for soil protection in these systems and can influence the diversity and richness of the rhizospheric microorganism community in the soil . ArbuscuDifferent species of cover crops are used in sustainable agricultural management in the Brazilian Cerrado region, which is considered one of the main agricultural frontiers of today . Among tNitrogen availability is another factor to be considered when handling vegetation cover in the soils of tropical regions, such as the Cerrado. Nitrogen contributes to plant biomass protein, providing more efficient soil protection, and when managed before planting, vegetation cover promotes more efficient nutrient cycling for subsequent crops . This maGiven its importance in the regional development of agriculture in the Cerrado region, understanding the biodiversity of arbuscular mycorrhizal fungi associated with the main cover crops used in conservation systems is of fundamental importance for the effective management of management practices in this region .The objective of this work was to evaluate the occurrence of mycorrhizal fungi and glomalin content in soil under different cover crops cultivated after corn crops, with and without nitrogen (N) addition in the cover.Zea mays L.) in succession to the cover crops was planted in 2005 in an area of Embrapa Cerrados in Planaltina, DF . Between 1995 and 2005, the area was in the field. The soil of the experimental area is classified as typical dystrophic Red Latosol, Moderate A, and tropical Cerrado phase, with smooth wavy relief, and clayey texture  and the occurrence of periods of drought during the rainy season , ceará wild beans , Guandu “BRS mandarin” [Cajanus cajan (L.) Millsp.], Millet “BR05” [Pennisetum glaucum (L.) R.Br.] and Sorghum “BR 304” [Sorghum bicolor (L.) Moench]. The absolute control of the experiment was the treatment without the use of cover crops, that is, the vegetation of spontaneous occurrence in the area (Spontaneous Vegetation). The plant density was 20 plants per linear meter for C. juncea, Guandu, sorgo, wheat, and Brachiaria ruziziensis; 40 plants per linear meter for millet and turnip; and 10 plants per linear meter for wild beans. The spacing between sowing lines was 0.5 m for all plant species  until 2012. In the flowering period of the cover plants, roots and rhizosphere soil were collected at a depth of 0–20 cm with Dutch trade in June 2012. From each of the treatments, a composite sample consisting of three subsamples of random points in the subplot was taken, and these composite samples were homogenized and transported to the Soil Biology Laboratory of Agronomy-UnB.The spores were extracted from the soil using 50 ml of each composite sample by the wet sieving technique , followeFor the identification of AMF species from morphological characteristics, spores were separated according to their morphotypes and mounted on blades with pure polyvinyl-lactoglycol (PVLG) and PVLG mixed with Melzer (1:1 v/v). The identification of mycorrhizal fungi species was performed in the Mycorrhizas Laboratory of Embrapa Agrobiologia, following the descriptions of the reference cultures present in the International Culture Collection of Arbuscular and Vesicular-Arbuscular Mycorrhizal Fungi .The data were submitted to variance analysis by the Assistat  analysesThe analysis of variance Table 1 C. juncea had the highest number of spores compared with the other treatments, and the soil under millet had the lowest spore density values. The treatments using wild beans from Ceará, sorghum, and spontaneous vegetation showed intermediate values of spore density , with the application of nitrogen in the corn cover, the species G. microaggregatum, Gigaspora sp., and S. persica, which occurred only in this treatment. On the other hand, in the treatments without the application of nitrogen in topdressing in the corn crop, the identified species were A. scrobiculata and G. tortuosum. The species Ar. leptoticha, G. macrocarpum, S. gregaria, and S. pellucida were identified in both treatments, with and without nitrogen application.In millet rhizospheric soil, with and without nitrogen application in topdressing in the corn predecessor crop, the following species were identified: G. microaggregatum, S. gregaria, G. clavisporum, and A. foveata present little proximity to the analyzed cover, which indicates the chance of the appearance of these species in the rhizosphere of the plants studied.When considering only the cover crops Figure 2The canonical correspondence analysis showed a correlation between the occurrence of the species of arbuscular mycorrhizal fungi identified with the cover crops with and without N application Figure 3C. juncea rhizosphere, the frequency of AMF species did not differ in treatments with and without nitrogen application  in the treatment with nitrogen application in topdressing in the corn crop was lower than that in the treatment without nitrogen application (567.83 spores/50 g of soil).There are few studies that evaluate the influence of the effect of applying nitrogen fertilizer to corn crops in succession to cover crops on the mycorrhizal population. However, The verified spore density data can be considered high. This finding can be explained by the seasonal characteristics of the region where the plants were grown. The Cerrado is a region that has two well-defined climatic seasons, the dry season and the rainy season . The behC. juncea, millet, Guandú + millet, C. juncea + millet, and spontaneous vegetation with the application of four nitrogen rates  on the rate of mycorrhizal colonization and did not find significant differences between the treatments. The mycorrhizal colonization was between 58% and 63% in the soil under the different cover plants.Despite the mycorrhizal colonization rate being similar among cover crops, other works, such as C. juncea, jack bean, Guandú, velvet bean, and sorghum in succession to crops in agroforestry systems in the Cerrado and found that the highest levels of glomalin were observed in treatments with velvet bean and C. juncea in succession to maize and beans. Lower levels were observed in bean plots in succession to jack bean and Guandú.Although it is not possible, with the analyses carried out in this work, to state that the quantified glomalin is totally produced by soil mycorrhizal fungi, its values constitute an important parameter of microbial activity in the soil . Soil glAcaulospora, Archeospora, Glomus, Gigaspora, and Scutellospora were identified in the rhizosphere of C. juncea, sweet bean, sorghum, Guandú, millet and spontaneous vegetation, with and without nitrogen application (Soil turning destroys fungal hyphae and thus negatively influences AMF production of glomalin. Aggregate and glomalin t values, in areas even after 3 years of no-tillage system, were substantially lower when compared to values observed in areas of continuous pasture for 15 years . Specieslication Table 5.lication .A. delicata, A. spinosa, G. caledonium, G. etunicatum, G. tortuosum, and S. persica were associated with the millet rhizosphere. A. laevis, G. microaggregatum, and G. etunicatum were associated with the rhizosphere of Guandú, A. spinosa, A. scrobiculata, G. etunicatum, G. geosporum, and Glosmus sp. in the C. juncea rhizosphere. The species A. spinosa, G. microaggregatum, G. claraideum, G. etunicatum, G. geosporum, and Scutellospora sp. were associated with spontaneous plants without nitrogen application. A. spinosa, A. scrobiculata, G. microaggregatum, G. etunicatum, G. geosporum, S. gregaria, and S. persica were detected in the rhizosphere of spontaneous plants with nitrogen application.G. microaggregatum that does not occur in the rhizosphere of cover plants, with or without the addition of N, but, only in the rhizosphere of spontaneous vegetation with the addition of N. Thus, it can be inferred that this species is adapted to soils with vegetation occurrence spontaneous in the area. However, further studies are needed on the dynamics of the diversity of this and other species of mycorrhizal fungi that occur in the rhizosphere of cover crops.In this work, a result similar to that found by C. juncea, millet, and spontaneous plants, as well as in the data of this work presented in Glomus, eight to Acaulospora, six to Scutellospora, one to Entrophospora, and one to Gigaspora.When analyzing the arbuscular mycorrhizal fungi community of cover crops in Cerrado agricultural systems, C. juncea, A. scrobiculata, A. mellea, Acaulospora sp., Gigaspora sp., G. tortuosum, S. scutata, and S. gregaria. A. scrobiculata, A. scavata, A. mellea, Ar. leptoticha, Gigaspora sp., G. macrarpum, G. tortuosum, S. scutata, and S. gregaria. The frequency of arbuscular mycorrhizal fungi found in the rhizosphere of spontaneous vegetation did not differ between treatments with and without nitrogen application in the top dressing (G. microaggregatum and G. tortuosum are not commonly found in the soil rhizosphere under spontaneous vegetation, indicating their occurrence by chance. All other arbuscular mycorrhizal fungi found in the rhizosphere of wild plants are commonly associated with these cover plant species.In soybean and corn rhizospheres cultivated in succession with dressing Figure 1A. scrobiculata, A. scavata, A. mellea, Gigaspora sp., G. microaggregatum, G. tortuosum, S. scutata, and S. gregaria.S. pellucida and S persica in C. juncea; Gigaspora sp. in sorghum; G. macrocarpum in Guandu; G. macrocarpum and G. clavisporum in millet; and G. microaggregatum and G. tortuosum in spontaneous vegetation.No influence of nitrogen application on soil spore density was verified, and among the cover crops studied, Guandu and Crotalaria presented the highest numbers of spores in the soil. There were no differences in the diversity of arbuscular mycorrhizal fungal species associated with the studied cover crops. The most frequent species associated with cover crops were The original contributions presented in the study are included in the article/Supplementary Materials. Further inquiries can be directed to the corresponding author.JM—Project coordinator and responsible for writing. MR—Work advisor. MK—advisor on mycorrhizae. OJ—responsible for mycorrhizal analysis. WJ—responsible for the experimental area and experiments. AC—responsible for the experimental area and experiments. LS—responsible for laboratory analysis. RS—responsible for statistical analysis. SD and SS—text review. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.The handling editor declared a past collaboration with authors JM, RS, and SS.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Chromolaena odorata (L.) R.M. King & H. Robinson is native to tropical America, and has naturalized in many other countries in tropical Asia, Austria, and West Africa. The species often forms dense thickets and reduces the native species diversity and population in the invasive ranges. The species is also considered as a noxious weed in agriculture fields, and listed in the 100 of the world’s worst invasive alien species. The characteristics of its life-history such as the seed production rate, growth pattern, and adaptative ability to the environmental conditions may contribute to the invasiveness of the species. Possible evidence of the defense capacity against the natural enemy, and the allelopathic potential against the competitive plant species for C. odorata has been accumulated in the literature over three decades. The extracts, residues, and/or rhizosphere soil of C. odorata increased the mortality of various insects and parasitic nematodes, and decreased their population. The extracts, residues, and/or rhizosphere soil of C. odorata also inhibited the germination and growth of several plant species including the indigenous plant species in the invasive ranges of C. odorata. Toxic substances, pyrrolizidine alkaloids were found in the leaves and flowers of C. odorata. These pyrrolizidine alkaloids may work as the defense agents against the natural enemies. Several potential allelochemicals such as flavonoids, phenolic acids, and terpenoids were also found in the plant extracts of C. odorata. Some of these compounds may work as allelopathic agents of C. odorata and inhibit the germination and growth of the competitive plant species. These characteristics of C. odorata for the defense function against their natural enemies such as insects and parasitic nematodes, and allelopathic potential against the competitive native plant species may contribute to the invasiveness and naturalization of C. odorata in the new habitats as invasive plant species. However, it is necessary to determine the concentration of these allelochemicals in the neighboring environment of C. odorata such as the rhizosphere soil since allelochemicals are able to work only when they are released into the neighboring environment. It is the first review article focusing on the defense function and allelopathy of C. odorata. Chromolaena odorata (L.) R.M. King & H. Robinson , belonging to Asteraceae, is a perennial shrub, and grows to 2–3 m in height, but it can scramble up other plants and reach 5–10 m in length. Its stems are cylindrical and pithy, become woody, and often branch in pairs from the axillary buds. The opposite leaves are ovate-triangular, 6–12 cm long and 3–7 cm wide with a 1–3 cm petiole, and smell a strong odor when they are crushed [ crushed ,5. Howev crushed .C. odorata is from southern Florida and Texas (30° N) to north-western Argentina (30° S) including the Caribbean islands [C. odorata was in the 1870s in Indo-Gangetic Plain [The native range of  islands ,11,12,13C. odorata infests in a wide range of natural vegetation such as grassland, savanna, bush, forest margins and gaps, dry deciduous and degraded forests. The species scrambles up to the canopy of trees, and spreads over the trees, eventually reducing the vigor of the trees [C. odorata was reduced by 31% [C. odorata also infests as a weed in agricultural lands such as oil palm, rubber, cacao, coffee, coconut and banana plantations, pastures, crop fields, and abandoned agriculture fields. The species is considered as a noxious weed in agricultural fields and commercial plantations [C. odorata is only weedy on some occasions such as after the fire, hurricane, human activity, and other destruction events. It is then forced out by the successional vegetation and disappears [he trees ,15,16. Ahe trees ,18. It whe trees ,20. Averd by 31% . C. odorntations ,23, and ntations ,12. In isappears ,25. Howesappears .It was estimated that approximately 10% of the introduced plant species could be established in the introduced ranges, and 10% of the established plants become invasive , which iC. odorata is also a prolific seed producer. It was reported to produce 2000 (1 year old C. odorata)–260,000 (10 year old) seeds per m2 with 20–46% of seeds being viable. The germination rate of the seeds collected from the seed banks was 5–20% [C. odorata from its underground stems, corms, arises quickly after the fire, and the regeneration of the species occurs [C. odorata dominated ecosystem.as 5–20% ,33. The as 5–20% ,35. The s occurs ,37. TherC. odorata in the introduced ranges was lower than that in the native ranges [C. odorata such as flower color, leaf shape, and plant shape is high in the native range, while there are only two main biotypes, Asia/West Africa biotype and South Africa biotype, in the invasive ranges [C. odorata obtained from invasive ranges were larger than those from the native ranges [C. odorata in the invasive ranges were smaller than those of the native ranges [C. odorata in the native ranges was 30% greater than that in the invasive ranges [Genetic diversity of e ranges ,39,40,41e ranges , while Se ranges ,43. Howee ranges ,45. Droue ranges ,45. It we ranges .C. odorata is allelopathic, and contains the compounds involved in the allelopathy. The plant species was also reported to show the defense response against the natural enemies such as herbivores and pathogens, and contain the compounds involved in the defense function. However, there has been no review paper focusing on the allelopathy and defense response of C. odorata, and compounds involved in these functions. This review provides an overview of the defense response and allelopathy of the species and compounds involved in the defense and allelopathy. Then, their possible involvement in the invasiveness of the species is discussed.Plants produce large number of secondary metabolites in many chemical classes. The biosynthesis of some secondary metabolites is induced or synthesized de-novo under certain circumstances. Many of these secondary metabolites in the invasive plants have been reported to show multiple functions such as anti-herbivore, anti-fungal, anti-microbial, and allelopathic activity, and contribute to increasing the fitness of the plants in the invasive ranges ,54,55,56C. odorata is controlled by many insects and pathogens in its native ranges [C. odorata, and 25% of them are specific species in the native ranges [C. odorata in the invasive range (South Africa) were counted [The interaction between the invasive plants and their natural enemies such as herbivores and pathogens, is one of the important factors for the naturalization of the invasive plants ,31,57,58e ranges ,60. Moree ranges . There m counted . Accordi counted ,64.C. odorata increased the mortality of leaf beetle, Callosobruchus maculatus Fabricius [C. odorata leaves also increased the mortality of adult weevil, Sitophilus zeamais Motschulsky [C. odorata induced the increasing larval mortality of black fly, Simulium spp. [Periplaneta americana Linnaeus [C. odorata were applied to Aabelmoschus esculentus (L.) Moench once a week for 4–7 weeks after its planning. The treatments resulted in the reduction of the population of whitefly, Bemissa tabaci Gennadius, and leafhopper, Amrasca biguttula Ishida on Aabelmoschus esculentus [C. odorata leaves also showed ovicidal, antifeedant, and larvicidal activity on a leaf-eating insect, Spodoptera litura Fabricius [C. odorata possess anti-insect activity and contain certain compounds involved in the activity.Powder of the roots, stems, and leaves of abricius ,66. Esseschulsky ,68. Aqueium spp. , and an Linnaeus . Aqueousculentus . The metabricius . These oC. odorata [N-oxide and intermedine N-oxide were identified in its roots [C. odorata may be involved in the anti-insect activity caused by the extracts and power of the species as describe above, and contribute to the protection of the species from herbivore attacks.Pyrrolizidine alkaloids such as 7- and 9-angeloylretronecine, intermedine, rinderine, and 3′-acetylrinderine were isolated from roots and mature flower heads of  odorata , and rints roots  , Helicotylenchus spp., and Pratylenchus spp. feed on the roots of plants, and their feeding process causes serious injuries and reduces the ability of the plants to absorb nutrients and water, leading to losing plant vigor and defense capability against other pathogen attacks [Meloidogyne spp., Helicotylenchus spp. and Pratylenchus spp., was suppressed by the C. odorata infestation into the invasive ranges with various soil conditions [C. dorata reduced by 77–81% of plant parasitic nematode population; Meloidogyne spp., Helicotylenchus spp., and Pratylenchus spp. in the soils after two years invention [C. odorata also suppressed the increasing population of Meloidogyne incoginita Kofoid & White in the pot experiments [C. odorata and accumulated in the soils, and these compounds may suppress the population of plant parasitic nematodes in the soils.Plant parasitic nematodes such as  attacks ,87,88. Tnditions . It was nvention . C. odoreriments . These oC. odorata into the field soil prevented the increasing population of Meloidogyne incoginita [C. odorata showed the suppression of the parasitism of Meloidogyne incoginita into the roots of Lactuca sativa L. [C. odorata may work for the suppression.The incorporation of plant powder of coginita . Aqueousativa L. . TherefoC. odorata and the compound showed anti-nematode activity [C. odorata [of C. odorata, and the soil under C. odorata may suppress the population of the nematodes, and prevented the hatch and parasitism of the nematodes. Certain compounds including 1,2-dehydropyrrolizine alkaloid may cause the suppression and acts as anti-nematode agents of C. odorata  was reported to be 50% of its native ranges (Puerto Rico) [The invasion of  odorata . The pop odorata . Arbuscu odorata ,98,99. T species ,101. Theto Rico) .C. odorata increased the population of the soil borne fungal pathogen, Fusarium ssp., and inhibited the growth of Amaranthus spinosus L. and Bambusa bambos (L.) Voss. Sterilization of the soil eliminated these effects. The root leachate of C. odorata increased the spore density of Fusarium spp. in C. odorata-free soil. The increases were illuminated by adding activated carbon into the soil [Sorghum bicolor (L.) Moench. and Vigna unguiculata (L.) Walp. increased the population of Fusarium spp. [Glycine max (L.) Merr. increased the population of Fusarium spp. [C. odorata may stimulate the increasing population of Fusarium spp. However, it is not clear if the increased Fusarium spp. population affects the growth of C. odorata.The rhizosphere soil of the soil . It was ium spp. , and pheium spp. . The obsC. odorata suppressed the growth of some soil borne fungal pathogens including Fusarium spp. Aqueous methanol leaf extracts of C. odorata significantly suppressed the colony growth of the pathogens, Lasiodiplodia theobromae (Pat.) Griffon & Maubl. and Lasiodiplodia pseudothobromae A.J.L. Phillips, A. Alves & Crous [Lasiodiplodia spp. are members of the Botryosphaeriaceae family and cause leaf necrosis, canker, and dieback in many plant species [C. odorata suppressed the growth of Bacillus subtilis Cohn, and Bacillus cereus Frankland & Frankland [C. odorata suppressed the growth of soil borne pathogen fungi, Phytophthora colocasiae Racib., and Fusarium oxysporum Schlecht. emend. Snyder & Hansen [C. odorata also suppressed the colony growth of the pathogen fungi, Pythium ultimum Trow, Rhizoctonia solani J.G. Kühn, Fusarium oxysporium Schlecht. emend. Snyder & Hansen, and Phytophthora nicotianae Breda de Haan [Pyricularia oryzae Cavara [C. odorata suppressed the growth of Rhizoctonia solani J.G. Kühn, Fusarium graminearum Schwabe, Exserohilum turcicum (Pass.) K.J. Leonard & Suggs, Botrytis cinereal Pers., and Sclerotinia sclerotiorum (Lib.) de Bary [C. odorata possess the anti-fungal activity, and may contain certain compounds involved in the activity.On the contrary, it was reported that the extracts of  & Crous . Both La species ,108. Therankland . The eth& Hansen . Acetone de Haan  and Pyrie Cavara . Essenti de Bary . These oC. odorata may be involved in the alteration of the microbial community as the observations in those publications  and invasive (China) ranges, were germinated and grown in a field in China under natural condition for 10 months. The biomass of C. odorata seeds obtained from the invasive range was greater than that from the native range. Both the C. odorata from Mexico and China were grown together with other plant species from Mexican origin and those from Chinese origin. The biomass of the C. odorata seed variety grown with Chinese original plant species was greater than that grown with Mexican original plant species, while these Mexican original plant species grew well with both C. odorata than the Chinese original plant species [C. odorata than the Chinese original plant species. The co-evolutional history of the neighboring plant species in the native ranges of C. odorata are longer than the plant species in the invasive ranges, and those neighboring plant species in the native ranges may have more competitive ability to C. odorata than the plant species in the invasive ranges. These observations may be consistent with the novel weapons hypothesis described above.The seeds of  species ,115,116.C. odorata in its plant residues and extracts from different plant parts of C. odorata  Gaertn., Cyperus iria L. and Ageratum conyzoides L. [Lycopersicon esculentum Mill. [C. odorata also suppressed the growth of Crassocephalum crepidioides (Benth.) S. Moore [C. odorata leaves contain some allelochemicals, and those allelochemical were released into the soil during their decomposition process.The incorporation of ngena L. . The leaoides L. , and Lycum Mill. . The leaS. Moore . These oC. odorata suppressed the germination and growth of five plant species from the native ranges of C. odorata such as Bidens pilosa L. , Ageratum conyzoides L. , Amaranthus spinosus L. , Conyza sumatrensis (Retz.) E. Walker (South America), and Chenopodium ambrosioides L. , and other five plant species from the invasive ranges such as Rottboellia exaltata (Lour.) Clayton , Digitaria sanguinalis (L.) Scop. , Hemisteptia lyrata Bunge. (Eurasia and north Africa), Youngia japonica (L.) DC. (Eastern Asia), and Dicliptera chinensis (L.) Juss. (Eastern Asia). Growth inhibitory effect on these ten test plant species was higher with the leaf extracts than the root extracts of C. odorata, and on plant species from the invasive ranges than that from native ranges of C. odorata [C. odorata collected from invasive ranges (China) was higher than that collected from native ranges (Mexico) against the growth of the indigenous plant species in China; Eupatorium japonicum Thunb., Eupatorium stoechadosmum Hance and Eupatorium lindleyanum DC [C. odorata extracts from the invasive ranges was greater than that from the native ranges, and the plant species from its invasive ranges were more susceptible to the extracts than those from the native ranges of C. odorata.Aqueous extracts of leaves and roots of  odorata . It was yanum DC . Those oLathyrus sativus L. were dipped in the aqueous leaf extract of C. odorata for 8 h, washed with distill water, and dried. Then, the seeds were sown and the germination and growth of Lathyrus sativus were determined after 10 days and 30 days, respectively. The treatments resulted in the suppression of the germination and the growth of Lathyrus sativus [The seeds of  sativus . The obsC. odorata showed the suppression of the germination of weed plant species, Cynodon dactylon L., Crassocephalum crepidioides (Benth.) S.Moore, and Ageratum conyzoides L. [Eleusine indica (L.) Gaertn., Cyperus iria L., and Ageratum conyzoides L. [C. odorata inhibited the germination and growth of Echinochloa crus-galli (L.) P.Beauv., and Amaranthus viridis L. [Aqueous leaf extracts of oides L. , and theoides L. . Aqueousridis L. .C. odorata also inhibited the germination and growth of crop plant species, Sorghum bicolor (L.) Moench, Zea mays L., Phaseolus vulgaris L., Vigna radiata (L.) R.Wilczek, and Centrosema pubescens Benth. [Brassica chinensis L. [Glycine max L., and Gossypium hirsutum L. [Lycopersicum esculentum Mill. [C. odorata inhibited the germination and growth of Sesame indicum L., Brassica nigra (L.), Brassica juncea (L.) Czern., and Raphenus raphanistrm L. [C. odorata were extracted with methanol, and the extract was sprayed to Amaranthus spinosus L. and Amaranthus spinosus L. The treatments resulted in the reduction of the growth parameters of both plant species such as their plant high, leaf areas, root length, and plant masses [Aqueous leaf extracts of s Benth. ,129,130,ensis L. , Glycinesutum L. , and Lycum Mill. . Aqueousistrm L. . The leat masses .C. odorata possess allelopathic activity on the germination and growth of both weed and crop plant species, and may contain water and/or methanol extractable allelochemicals. Effectiveness of these allelochemicals was greater on the plant species from the invasive ranges than the native ranges of C. odorata.These observations suggest that the aqueous and methanol extracts of all parts of C. odorata on the germination and growth of several plant species was also investigated. Aqueous leaf extracts of C. odorata suppressed amylase activity in the seeds of Cicer arietinum L., and Cajanus cajan (L.) Millsp. [C. odorata were sprayed onto 21-day-old plants of Ageratum conyzoides L. every two days for 28 days. The treatments resulted in the reduction in the contents of chlorophyll, carotenoids, and stomata number in the leaves of A. conyzoides [C. odorata were soaked in water for 48 h, and the soaking water also reduced the contents of chlorophyll and protein, and cell division of Allium cepa L. [C. odorata suppressed chlorophylls and carotenoid contents in the leaves of Echinochloa crus-galli (L.) P.Beauv. [C. odorata . Total terpenoids, flavonoids, phenols, and steroids were also determined in the ethanol extracts of C. odorata [C. odorata are allelopathic and contain allelochemicals. Allelochemicals in the extracts of C. odorata should be identified in the furfure. C. odorata described in the The inhibitory mechanism of the extracts of  Millsp. . Aqueousnyzoides . The lea cepa L. . The hexP.Beauv. . These oP.Beauv. ,139. Tot odorata . HoweverSome of the plant secondary metabolites function as defense molecules against herbivores, pathogens, and competing neighboring plants. These compounds are important for the plant’s survival and fitness, and represent the adaptive characters of the plant species that have been subjected to natural selection during the evolution. The pattern of the plant secondary metabolites is complex, and changes in an organ- and tissue-specific way, and during the developmental stages of the plants. The biosynthesis of some secondary metabolites is induced or synthesized de-novo upon herbivore-attack, pathogen–infection and competition with neighboring plants ,143,144.C. odorata obtain from the native ranges (USA) and that from the invasive ranges (South Africa) were observed by the ultra-performance liquid chromatography-mass spectrometry. The major differences were high concentrations of flavonoids and flavone glycosides in the C. odorata from the invasive ranges comparing to those from the native ranges [C. odorata are not apparent, the observation suggests that the invasive plant species may employ the metabolic flexibility and/or rapid adaptive evolution to succeed as the invasive plant species.The significant difference in the metabolomic profiles between e ranges . AlthougC. odorata collected from invasive ranges was higher than that collected from the native ranges [C. odorata obtained from the invasive ranges (China) was greater than that from the native ranges (Mexico) [C. odorata in the invasive ranges  than those in the native ranges  [C. odorata obtained from an invasive range was 2.4-fold greater than that from the native ranges. However, the specific compounds of the increasing phenolics were not identified. The function of these flavonoids on the allelopathy of C. odorata is also not clear. In addition, the chemical structure of odratin in the publication is not correct [As already described in the e ranges ,125. Tot(Mexico) . Concent Tobago) . The con correct   P.Beauv. and Senna obtusifolia (L.) H.S.Irwin et Barneby, and reduced all stages of mitosis of the root tips of Allium cepa L. [C. odorata and showed anti-herbivore and anti-nematode activity as already described in the Several terpenoids were identified in the essential oil and leaf extracts of  odorata ,148. Ter odorata ,178,179. odorata ,181,182.extracts . α-Pinenium Cav. . 1,8-Cin cepa L.  (Figure C. odorata may affect the physiological processes of the neighboring plant species, causing growth inhibition and reducing their fitness as allelochemicals. Pyrrolizine alkaloids found in C. odorata may also have defense functions against herbivores, and pathogenic fungi, microbes, and nematodes. Therefore, these compounds may contribute to the invasiveness and naturalization in the introduced rages of C. odorata.As describe above, some of cinnamic acid and benzoic acid derivatives, flavonoids, and terpenoids found in C. odorata is highly invasive and has naturalized in many countries. The paper described the interaction between the species and their natural enemies, and the species and the indigenous plant species in the invasive ranges for the naturalization of the invasive plants. The extracts of all plant parts, residues, and rhizosphere soil of C. odorata showed the inhibitory activity against various insects, parasitic nematodes, and fungal pathogens, and several pyrrolizidine alkaloids were identified in the roots and flower heads of C. odorata. Pyrrolizidine alkaloids are toxic against insects and other organisms. Therefore, pyrrolizidine alkaloids of C. odorata may act as chemical protection agents against natural enemies including herbivores.C. odorata were more susceptible to the extracts than plant species from the native ranges of C. odorata. Those observations suggest that C. odorata possess allelopathic activity, and may contain certain allelochemicals. These allelochemicals may be more effective on the plant species from the invasive ranges of C. odorata than on the plant species from its native ranges.The rhizosphere soil, extracts, and residues of all plant parts showed the suppression of the germination of growth of many plant species including indigenous plant species in the invasive ranges. The indigenous plant species from the invasive ranges of C. odorata contains secondary metabolites in many chemical classes, such as phenolic acids, flavonoids, saponins, tannins, and terpenoids. Although many of these compounds have not been related to the allelopathy of C. odorata, benzoic acid and cinnamic acid derivatives such as p-hydroxybenzoic acid, protocatechuic acid, and p-coumaric acid; flavonoids such as sakuranetin, quercetin and kaempferol; and monoterpenes such as α-pinene and 1,8-cineole identified in the leaves of C. odorata were reported to be involved in the allelopathy of other plant species. Therefore, these compounds may also work as allelopathic agents for C. odorata and inhibit the germination and growth of the neighboring plant species.Pharmacological investigations showed that C. odorata for the defense function against their natural enemies such as insects, parasitic nematodes, and fungal pathogens, and allelopathic potential may contribute to the invasiveness and naturalization of C. odorata in the new habitats as invasive plant species. However, allelochemicals are able to work only when they are released into the neighboring environment of the donner plants either by root exudation, volatilization, rainfall leachates, or decomposition of plant litter and residues. Therefore, it is necessary to determine the concentration of these allelochemicals in the neighboring environment of C. odorata such as the rhizosphere soil.These characteristics of


Multiple-input Multiple-Output (MIMO) systems require orthogonal frequency division multiplexing to operate efficiently in multipath communication (OFDM). Channel estimation (C.E.) is used in channel conditions where time-varying features are required. The existing channel estimation techniques are highly complicated. A channel estimation algorithm is needed to estimate the received signal’s correctness. In order to resolve this complexity in C.E. methodologies, this paper developed an Improved Channel Estimation Algorithm integrated with DFT-LS-WIENER (ICEA-DA). The Least Square (L.S.) and Minimum Mean Square Error (MMSE) algorithms also use the Discrete Fourier Transform (DFT)-based channel estimation method. The DFT-LS-WIENER channel estimation approach is recommended for better BER performance. The input signal is modulated in the transmitter module using the Quadrature Phase Shift Keying (QPSK) technique, pulse modeling, and least squares concepts. The L.S. Estimation technique needs the channel consistent throughout the estimation period. DFT joined with L.S. gives higher estimation precision and limits M.S.E. and BER. Experimental analysis of the proposed state-of-the-art method shows that DFT-LS-WIENER provides superior performance in terms of symbol error rate (S.E.R.), bit error rate (BER), channel capacity (CC), and peak signal-to-noise (PSNR). At 15 dB SNR, the proposed DFT-LS-WIENER techniques reduce the BER of 48.19%, 38.19%, 14.8%, and 14.03% compared to L.S., LS-DFT, MMSE, and MMSE-DFT. Compared to the conventional algorithm, the proposed DFT-LS-WIENER outperform them. Enabling 5G technology is recognized by MIMO in mobile communications . PerformMIMO transmission will be a significant part of wireless communication in the coming days in wireless technology. This type of system has minimum difficulty executing OFDM and is simple. In contrast, in the case of non-orthogonal multi-carriers, the MIMO structure of the receiver has become more complicated since it has to handle various interference measurements, i.e., inter-symbol interference (I.S.I.), inter-carrier interference (I.C.I.), and inter-antenna interference (I.A.I.) ,10,11. TIn ref. , it was It can also be referred to by correctly localizing the pilot energy up to the terminated point of the block. It needs to possess maximum energy while it is copied to the C.P. Identification of symbols in the data of non-orthogonal multi-carriers and acquires the various Channel Estimation and C.Q. modules independent of the usual practice. The earlier works on Channel Estimation  were calChannel Estimation (C.E.) utilizes C.S.I. to transmit and receive the wireless signal. In a wireless communication medium, C.S.I. causes power degradation, fading, and wave scattering as a function of transmission distance. The channel state information (C.S.I.) is determined by comparing the pilot signals used during the transmitter to the received pilot signals. In contrast, the SNR reflects the resilience of the bit stream about the channel noise. The concept of C.E. is evolving based on the objective of the correlation of signal at the center point integrated with suppression of the M.A.I. This signal quality impacts receiver BER performance . In C.E.Currently, for uplink MU-MIMO communication, countless MIMO detectors are used. In addition, an optimal maximum likelihood detector and a low-complexity environment are also developed.The channel estimate is crucial in OFDM systems. Enhancing the system’s bit error rate performance is utilized to boost the channel capacity of an OFDM system. Based on a comb-shaped pilot array, channel estimation is performed on the pilots, and a Rayleigh fading channel is considered.A performance measure of the M.S.E. of the channel estimator fusing DFT-based procedure obtains the best results as contrasted with the consolidation of LS-based strategies. The comparative analysis is carried out by varying parameters, such as the number of subcarriers, channel taps, cyclic prefix length, and pilot frequency.This article recommends a channel estimation method incorporating differential evolution and L.S. with DFT. The proposed ICHE-DA is included in the central part of the OFDM-MIMO block. We consider a two-user interference channel for MIMO-OFDM systems. We demonstrate the basic idea of a user-based transmitter and receiver using DFT-LS-WIENER. Further, we focus on interference from frequency-selective channels. By doing so, the main struggle is to evaluate the accuracy of covariance matrices, which may need accurate information on interference parameters. Moreover, one of the contributions is to analyze the firmness of the spectrum by coinciding with the DFT series. The findings showed that the suggested system outperforms the current technique in terms of BER, PSNR, CC, and MMSE.In an ideal radio channel, there would only be one direct path signal, a flawless recreation of the transmitted signal. On a natural channel, the signal is altered during transmission. Copies of the transmitted signal that have been attenuated, reflected, refracted, and diffracted make up the received signal. Additionally, the channel puts noise into the signal and causes the carrier frequency to shift as the transmitter or receiver moves (Doppler effect). A radio system’s performance depends on the radio channel’s characteristics. Therefore, understanding these effects on the signal is crucial. As a result, in our work, we consider a MIMO-OFDM system before employing pilot permutation to estimate the channel. This article compares the L.S., MMSE without DFT, and the L.S., MMSE with DFT. A new DFT-LS-WIENER hybrid channel estimation technique is also proposed to improve bit error rate performance.The rest of the paper is organized as follows: In their introduction of the MIMO-OFDM for hybrid channel estimator, Nie et al.  underlinQiao et al.  determinAlkhateeb et al.  anticipaThe estimation of the channel covariance matrix of the received sampled signals in the frequency domain is proposed by Ngo et al. . An asymZarifi et al.  proceedeThe angular resolution is improved by utilizing redundancy samples containing substantially more uniform DSFT premises than the antenna numbers proposed by Lee et al. . DSFT nuLi et al. propose the Minimum Mean Square Error (MMSE) scheme with second-order statistics . The limThis work presented an improved channel estimation algorithm DFT-LS-WIENER integrated with a differential approach. Moreover, this paper uses the L.M.DFT approach for channel estimation in the wireless communication medium. The middle area of the MIMO framework is where the suggested DFT-LS-WIENER is located. MIMO systems typically include several transmitters and a receiver antenna for parallel data transmission. The proposed model is examined for two transmitters and four-receiver antennae. Quadrature Phase-Shift Keying modulation (QPSK) is utilized for input modulation on the transmitter side ,45,46,47If signal bandwidth is more effective than channel bandwidth, it leads to signal distortion. This distortion is observed in the I.S.I. environment. To control I.S.I. in wireless communication, a pulse shaping filter (P.S.F.) is utilized for analysis. On each transmitter side, symbol mapping and IFFT operations are performed. Subsequently, this leads to transmitting information over the Multipath channel and includes AWGN noise on the receiver side. At the receiver, this operation is performed inversely with the utilization of DFT-LS-WIENER. With the utilization of LMMSE and DFT, a semi-blind review is performed. All of the subcarriers have been modulated using different techniques. The results have been simulated using the QPSK modulation technique. The next step in aligning the bit stream over the subcarriers is the mapping of the subcarriers. In the OFDM design, the Wiener filter is employed because it reduces the mean square error between the actual transmitted signal and the received signal. Here, L = 7 is the Wiener filter order under consideration. Initially, the incoming signal information is transmitted through pilot sequences and modulation schemes such as the QPSK scheme ,49. The The signal shift consists of ‘4’ signal states with the transmission of information through the QPSK scheme as 2 bits/symbol. Each signal in the system is modified by 1 bit thanks to the encoding strategy. The transmitted signal is represented by the sine and cosine of the following Equation (1):Here, In the modulator of the MIMO scheme, 4 phases of the signal are generated, which consists of 2D signal space with unit function From the above, Equations (2) and (3) Here, the system’s full power, distributed equally between the two carriers involved, is represented by the signal factor 1/2. At the receiving end, the symbols are demodulated by removing the carrier phase factor, and the continuously received robot in phase 2 is determined from the input data.Let Here, Equation (5) represents/denotes noise placed in the uncorrelated spatial and temporal region and/or represents the presence of noise in transmitting the time-domain signal at their antenna. After the removal of I.S.I., with the utilization of IFFT, ISI is eliminated. Moreover, it uses the symbol mapping technique at each transmitter side. Fourier analysis is performed in frequency domain components for signal transmutes in time or spatial domain factors. IFFT is implemented at the receiver end to improve flexibility, execution speed, and precision. Different complexes and data points are transformed for the same number of time-domain points when the IFFT procedure is used. The IFFT involved in the execution of N-point receiver operation in Equation (6) IFFT is presented mathematically as follows: k = 0, 1, …, N − 1, and kth end. Then, FFT analysis transforms the signal in the receiver block in the time domain. The following is the mathematical formulation for the FFT in Equation (7).The represented data frame transforms where/the size or the number of signal points. Moreover, the information is passed in a multipath channel environment with added AWGN noise characteristics. Instead of the message signal, AWGN is used in this document due to its higher bandwidth. The example that follows shows how system n’s noise generates a vector that has the same components as the message defined in Equation (8) and a random stationary point with mean 0 of a complex Gaussian distribution:0 = 1/T0, where T0 is the signal’s period. This translates to a frequency of 1/N for discrete-time transmissions. Since all other frequencies are multiples of this fundamental frequency, the resolution of the spectrum is determined by the number of samples N. At k = N/2, it is possible to determine the highest signal frequency that X[k] may represent. According to Shannon’s sampling theorem, the highest frequency of the original signal, which is assumed to be an audio stream sampled at 44.1 kHz, is 44.1/2, or 22.05 kHz. In the case of N = 1024 samples, the coefficient at k = N/2 corresponds to a frequency of 22.05 kHz, and the coefficient at k = 1 to a frequency of 22.05/512 43.1 Hz. The DFT coefficients would represent various frequencies  if we sampled another area of an audio signal with just 1000 samples (at the same sample rate). According to the conclusion, the spectra can only be compared if the DFT spectra are computed using the same number of samples. The second numerical sample demonstrated another impact on the resolution. The DFT spectrum cannot fail to reflect the genuine contribution of the individual frequencies of an arbitrary signal x[n], even if the signal is periodic because it is sampled, i.e., it only has information about particular discrete frequencies.When a signal is delivered, the fundamental frequency is fA receiver with channel estimation and MIMO detection is proposed using LS-DFT with overlapping pilots. Without sacrificing generality, each subcarrier in each frame-block is assumed to have a pilot, i.e., NF = NT = 1, yielding N(T.S.) = N.N.T., and pilot existence of multiple or redundancy N.R. = N (T.S.)/N.G. The phase difference of the received signal causes multipath fading. This is because the signal strength moves over varying distances and paths. Use a Rayleigh distribution to reach the receiver via multiple paths. For fast-fading situations, the Rayleigh distribution is most commonly used. The pilots are assigned by reusing the pilot sequence from the multiple request pilot requests themselves. The multi-objective optimization algorithm can easily optimize the time-varying channel metric. The proposed pilot allocation method has the potential to provide a powerful method for counting the sends with a request to users within their cells. The fitness function (F.F.) is a crucial component of evolutionary algorithms. The pilot pattern of multiple pilot requests is reused in this document for the pilot assignment. The optimization algorithm can optimize the channel measure that changes over time.The proposed pilot allocation method has the potential to provide a powerful method for counting the requesting users in their cells. The fitness function (F.F.) is critical to the receiver-side optimization concept.In order to develop a solution for parallel search optimization and the continuous process, the DFT-LS-WIENER technique is proposed. Because control parameters are included, the suggested DFT-LS-WIENER offers improved convergence benefits. With efficient continuous variable handling and integer variable optimization, the suggested DFT-LS-WIENER is provided in canonical form.If ‘Z’ is sent through a channel ‘j’ such that it can be written in matrix form as,Then, the error ‘e’ can be defined asThe definition of the squared error (S) isBy taking the derivative with respect to ‘j’ and setting it equal to zero, we may minimize this equation. The result of the final equation is:Both SISO and MIMO systems can use Equation (14).At the pilot frequencies, channel estimation is performed using the Least Squares (L.S.) approach. In this case, DFT-based channel estimation is used. As a result, the channel answers are shortened to the number of channel taps before being approximated using the least square method.After completing the DFT-based LS estimation, the estimates are fed to the Wiener filter model.The goal of applying the Wiener filter model in channel estimation is to decrease the quantity of noise in a noise-affected signal and to decrease the mean square error between the actual broadcast signal and the received signal.Wiener coefficients are produced based on the order of the Wiener filter; for example, if the order is six, then the Wiener filter model produces six Wiener coefficients.DFT-LS estimates are filtered using these Wiener coefficients.The desired output is a noiseless channel estimate.By applying linear time-invariant (L.T.I.) approaches to filter a noisy experimental process, a Wiener filter is a signal processing filter that generates an estimate of a desired or target stochastic process. The Wiener filter decreases the mean squared error between the estimated and predicted random processes. By using the pertinent signal as input and filtering the known signal to obtain an estimate as output, a Wiener filter aims to compute a statistical estimate of an unknown signal. For instance, an interesting unknown signal tampered with by additive noise can be present alongside a known signal. It is possible to estimate potentially important signals using Wiener filters to remove noise from distorted signals. A typical deterministic filter’s frequency response is designed for the selected carrier frequency. The Wiener filter, however, is created differently. To develop a linear time-invariant filter whose output is as close as possible to the original signal, one must be aware of the spectral properties of both the original signal and noise.ls[n]. The DFT-LS estimates (Hls[n]) are supplied to a Wiener filter with coefficients a0, a1…aN of order (number of touches passed) N in order to produce the Wiener filter coefficients. The expression’s result, x[n], is used to signify the filter’s output. The difference between the estimated and original signals is reduced to a minimum via the Wiener filter model. It significantly reduces root mean square error and improves bit error rate performance. The block diagram of the F.I.R. Wiener filter with DFT_LS estimates as input is shown in The output of the Wiener filter g[n] is compared with the reference signal s[n] after being convolved with the input signal HThis research was conducted to determine and compare the proposed algorithm’s performance to that of other systems. To evaluate the proposed approach system performance, the measures that will be evaluated are BER, M.S.E., and MMSE. The proposed algorithm measures network performance by varying the system’s SNR concerning the number of receiver and transmitter antennas. The suggested algorithm is run using machine configuration on the MATLAB platform.Here, the proposed ICEA-DA with LS FFT is utilized to analyze the system’s performance. The metrics considered for analysis are expressed as follows:In characterizing data channel performance, it is used as an essential parameter. At the remote end, errors in critical parameters appear while transmitting data from one to another point in wireless link/radio or wired telecommunication link.It is calculated as the average squared deviations between estimated and actual values. Its risk function is equivalent to the predicted values of error function loss.A comparison of the simulation and analytical results, which yield the M.S.E. and BER of equalization generated by DFT-based then Wiener channel estimators, is shown in The performance of the proposed method is checked against state-of-the-art  and modulation-free schemes. The parameters considered in the analysis are L.S., MMSE, BER, and PSNR. The details of the comparison are presented in the following sections. In The proposed DFT-LS-WIENER estimate performs better than L.S., LS-DFT, MMSE, and MMSE-DFT channel estimation algorithms in terms of BER performance for the channel estimation of MIMO-OFDM. When the number of subcarriers increases, the bit error rate is reduced. As the number of channel taps increases, the bit error rate also increases. As the cyclic prefix length increases, the bit error rate is reduced considerably. When the pilot frequency is increased, the bit error rate is also increased. Including the DFT technique in L.S. and MMSE improves the bit error rate performance. The computational complexing and time complexity of the DFT-LS-WIENER algorithm depends on the number of transmitting and receiving antennas in the system. If the number of transmitting antennae is N and the number of receiving antennae is M, then its time and computational is N*M. The accuracy of the proposed technique is high compared to the L.S., MMSE, LS-DFT, and MMSE-DFT channel estimation algorithms. Compared to the proposed approach, the efficiency of the introduced method attained 85%, 79.5%, 84.9%, and 84.1% compared with L.S., MMSE, LS-DFT, and MMSE-DFT. The proposed DFT-LS-WIENER algorithm is less complex and very easy to implement. The demerits include introducing the Wiener model in channel estimation, increasing the cost of implementation, and extra circuitry required for implementing the Wiener filter model. Our future works include implementing other adaptive filters such as the Kalman and Kernal filters in the channel estimation algorithms. Further, there will be minimal hardware implementation using the proposed methodology, and it will be simultaneously carried out without compromising the proposed methodology’s performance.


The gut microbiota is composed of a large number of microorganisms with a complex structure. It participates in the decomposition, digestion, and absorption of nutrients; promotes the development of the immune system; inhibits the colonization of pathogens; and thus modulates human health. In particular, the relationship between gut microbiota and gastrointestinal tumor progression has attracted widespread concern. It was found that the gut microbiota can influence gastrointestinal tumor progression in independent ways. Here, we focused on the distribution of gut microbiota in gastrointestinal tumors and further elaborated on the impact of gut microbiota metabolites, especially short-chain fatty acids, on colorectal cancer progression. Additionally, the effects of gut microbiota on gastrointestinal tumor therapy are outlined. Finally, we put forward the possible problems in gut microbiota and the gastrointestinal oncology field and the efforts we need to make. Chronic infection by H. pylori is the most well-described cause of noncardia GC  and cytotoxin-associated gene A (CagA)  . On the agosomes . Additioagosomes . Further stomach . Howeverongation . AdditioH. pylori induces chronic gastritis and peptic and duodenal ulcers and is linked to more than 90% of GC cases, only approximately 1 to 3% of infected individuals progress to GC   . Consistonous GC , 27. Furrichment . Thus, HH. pylori. Nasr et al. revealed the major studies in which non-H. pylori have been implicated in GC development before 2019 , can enhance gastrointestinal health, immune regulation, and cancer prevention . Even th species  which in species . In addi species , 44, whi species –47. Furt species , 49.Fusobacterium nucleatum (F. nucleatum), Bacteroides fragilis (B. fragilis), Escherichia coli (E. coli), Enterococcus, Campylobacter, Peptostreptococcus, Shigella, Klebsiella, and Akkermansia in CRC patients, and lower levels of Ruminococcus, Bifidobacterium, Eubacteria, and Lachnospira compared with healthy subjects  , which codes for the synthesis of colibactin, a genotoxin that induces DNA damage, cell cycle arrest, mutations, and chromosomal instability in eukaryotic cells. In addition, Iyadorai found that pks+E. coli was isolated in CRC patients  ; E. colipatients . Furthers of CRC , 93, andnescence . Howeverrobiotic .F. nucleatum, B. fragilis, and E. coli in CRC susceptibility or progression are supported by preclinical studies and clinical sample-based studies. In view of the complex interactions between bacteria, these three samples are not the only microbes important for CRC, but they provide insight into targetable mechanisms of action in CRC. In the future, more research is needed to elucidate the association between gut microbiota and CRC.In conclusion, the roles of Despite various explorations into the interrelation between gut microbiota and cancer, the exact mechanisms of this interaction are still unclear. It has been reported that this interplay may be related to bacterial metabolites. Here, we focused on short-chain fatty acids (SCFAs), one of the most important gut microbiota metabolites, and discussed the current studies on the association between SCFAs and gastrointestinal cancer.Bacteroidetes, whereas Firmicutes produce butyrate  could inhibit intestinal tumor development by suppressed the Wnt/B-catenin signaling pathway, and activated G-protein coupled receptors , a genetically tractable probiotic with a well-established human safety record, is emerging as a preferred chassis . Additionally, Kassan et al. evaluated the suitability of stool from candidate FMT donors for clinical use and suggested that only 3% of donors would pass such quality control assessments , the Medical Science and Technology Research Project of Henan Province (no. LHGJ20190675), and the Doctoral Research Start-up Foundation of Henan Cancer Hospital.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Laelia is an endemic genus of the neotropical region, with the greatest richness occurring in Mexico. A recent phylogenetic study transferred some Mexican laelias to the genus Schomburgkia, which has generated debate. The aim of the present study was to analyze the patterns of species richness and endemism and the current and potential geographic distributions of the taxa of Laelia s.l., as well as the putative Laelia s.s., distributed in Mexico as part of an exploratory evaluation of the generic limits to sheds light on the taxonomic debate and generate baselines to guide conservation efforts. A database was generated with information from herbarium specimens and publications. The species richness was estimated by political division, biomes, and elevation. The endemism was analyzed by political division and using the weighted and corrected weighted endemism indices. Geographic data, climatic, and topographic variables were used to predict the distributions with the maximum entropy algorithm. The results supported the proposal to transfer some species to the genus Schomburgkia. Some areas of the Sierra Madre del Sur and Oriental should be included as priority areas in the conservation strategies of Laelia. This study highlights the importance of the taxonomy, distribution, and hotspots in diversity conservation. Laelia Lindl. sensu lato (s.l.), is a genus comprising 25 species of epiphytic orchids restricted to the neotropical region, with its main center of diversity being in Mexico, but with a greater affinity towards the mountains [Laelia albida Bateman ex Lindl., Laelia anceps Lindl., Laelia autumnalis (Lex.) Lindl., Laelia furfuracea Lindl., Laelia gouldiana Rchb. f., and Laelia speciosa (Kunth) Schltr. are traditionally used to decorate offerings and tombs, as well as in traditional medicine to treat hemorrhages, wounds, dysentery, inflammation, and fever [ountains ,2. The sountains ,3. Due tountains ,4. In Mend fever .Given the problems in the delimitation of the genus and species, to date there is no consensus on the number of species recognized in Mexico. Halbinger and Soto-Arenas  reviewedLaelia has a long history of taxonomic changes, including the combination of Schomburgkia Lindl. with Laelia, which had already been proposed by Williams [Laelia s.l. were evaluated, found two strongly supported clades, one corresponding to elements endemic to Mexico and another that includes the taxa that were originally circumscribed to the genus Schomburgkia, whose species have a wider distribution. After analyzing the results and re-evaluating the morphology, as well as the taxonomic delimitation, the authors recognize both genera as valid and independent. Additionally, they transferred Laelia anceps, L. aurea A.V.Navarro, L. dawsonii (J.Anderson) De B.Crawshay, L. halbingeriana Salazar and Soto Arenas, L. rubescens Lindl., L. superbiens Lindl., and L. × oaxacana Salazar and R.Jiménez to Schomburgkia, leaving only L. albida, L. autumnalis, L. crawshayana Rchb.f., L. eyermaniana Rchb.f., L. furfuracea, and L. speciosa within Laelia sensu stricto (s.s.). Based on their results, the authors also treated L. gouldiana as a hybrid under the name of × Schombolaelia gouldiana (Rchb.f.) Peraza and Carnevali, and indicated that the parents are Schomburgkia anceps × Laelia autumnalis. After this publication, several authors continued considering this taxon in the species range and to the genus Laelia in its broad delimitation [The genus Williams  and takeWilliams . A recenWilliams , where 2mitation ,8,9,13.Laelia species, highlighting the importance of generating different sources of evidence that contribute to resolving this taxonomic uncertainty and at the same time providing information that is useful for the implementation of adequate strategies for their conservation and management.Said changes will not only reduce the number of recognized species for Mexico from 13 to six but the distribution of the genus will be restricted to the Mexican territory. The above has profound implications for the management and conservation of The knowledge about the current and potential distribution patterns of taxa and geographical areas with greater species richness provides essential information for understanding the processes that shape their diversity and generate basic information on conservation issues ,15. ThesLaelia have been addressed. However, no studies have addressed the current or potential distribution and richness patterns of the genus on a national scale. To contribute to this knowledge and generate useful information to establish strategies for the conservation and management of the species, as well as to explore additional evidence that clarifies the correct circumscription of the group, the present study aimed to analyze the current and potential geographic distribution and richness patterns of the taxa of Laelia s.l., as well as Laelia s.s. and species proposed to be transferred to Schomburgkia distributed in Mexico, following the circumscription proposed by Peraza-Flores et al. [To date, ethnoecological , phyloges et al. .Laelia were obtained, of which 860 corresponding to duplicate data; cultivated species; and purchased, incomplete, or confusing information were excluded. The final database consisted of 479 records, of which 19% had to be georeferenced and 2.5% needed nomenclatural corrections since synonymy errors were found. Among the most notable cases were Laelia crawshayana Rchb.f., where 100% of its records were found under the name of L. bancalarii R.González and Hágsater, which is currently invalid. Likewise, the names L. catarinensis Rosillo and Schomburgkia superbiens (Lindl.) Rolfe were commonly found in the databases and are currently synonyms of L. eyermaniana Rchb.f. and L. superbiens Lindl. respectively. No species were classified in a risk category according to the IUCN Red List [L. gouldiana stands out, as it is the only one in the category of ‘probably extinct in the wild’.A total of 1339 records of Red List . HoweverRed List . Among tLaelia s.l., which are distributed in 24 of the 31 states of the country  and L. eyermaniana (358–2850 m) had the widest altitudinal ranges. Laelia autumnalis is the only species that reaches altitudes above 3000 m, in contrast to L. aurea, whose upper elevational distribution range does not exceed 739 m, representing the most restricted elevational distribution range (135–739 m).According to the elevation distribution analysis, d 1500 m a. Accordd 1500 m a, L. ancL. speciosa was the one that registered the widest distribution in the country, located in 12 states, followed by L. autumnalis in 10 states. Jalisco (4), Nayarit (4), and Oaxaca (2) were the states with the highest number of endemic species, while L. crawshayana , L. furfuracea (Oaxaca), L. gouldiana , and L. halbingeriana (Oaxaca) were not recorded beyond a state limit, for which reason they are considered microendemic in this study.Of the species included in the genus, 77% (10 species) are endemic to Mexico . Of thesThe cells with the highest values of endemism discussed below are labeled with capital letters in When endemism values are weighted to remove the influence of species richness ), the results change slightly. Again, cells A and B recovered the highest values but were lower than those obtained with the WE index. Cell A, which previously had a value of WE = 1.72, now displays a value of CWE = 0.34, and cell B, which had a value of WE = 1.12, now shows a value of CWE = 0.37 b. Now, cLaelia s.s. is represented by seven species and two hybrids , Guanajuato (3), Michoacan (3), and Nayarit (3)  c. Oaxacamburgkia e. Both pmburgkia d,f. It sLaelia s.s. by the type of biome  distributed in humid mountain forests stand out. The species proposed as part of Schomburgkia show a greater affinity towards tropical seasonally dry forests and temperate forests, with five species each, followed by tropical humid forests with four species. On the other hand, the xerophytic scrublands are the least represented, with only S. anceps distributed in this biome. It is also possible to observe a distribution pattern with a greater affinity towards the lowlands of the Gulf and South Pacific slopes for this last genus. Meanwhile, Laelia s.s. shows its greater distribution towards the central-western and central-southern mountainous regions of the country.Regarding the distribution of of biome b, a greaLaelia s.s. develops between 358 and 3041 m a.s.l., with a greater affinity towards elevations between 1700 and 2500 m , Guanajuato, Michoacan, and Nayarit (3 each), with one being microendemic in Jalisco and another in Oaxaca. The largest number of endemic species assigned to Schomburkgia was found in Oaxaca (3), with two of them being microendemics. The WE index again showed two cells with the highest values of endemism, but these did not correspond to those detected for Laelia s.l. Cell F showed the highest index (WE = 0.61), followed by cell E (WE = 0.5), both located at the convergence of the PL and the SMS  located in the SMOR and cell J (WE = 0.45) in the SMS , Tamaulipas (TAM), PL, Veracruzan (VE), or the Yucatan Peninsula (YP)’s biogeographic provinces. One of the results worth highlighting is that the potential distribution of the species assigned to Schomburgkia, except for S. anceps and S. rubescens, is limited by the Trans-Mexican Volcanic Belt province (TMVB), since none of them is present in this province.The models presented AUC values similar to 0.8 and higher than 0.9, so the performance was good, while in others it was excellent according to Peterson et al. . The parrovinces , and excp = < 2 × 10−16) and ANOSIM  showed significant differences between the climatic variables for both putative genera  and ANOSIM , significant differences were detected. These differences were identified as occurring between ×Schombolaelia and Schomburgkia, as well as between Laelia s.s. and Schomburgkia in PC1, and only between Laelia s.s. and Schomburgkia in PC2 . The MTZ is a varied and complex area where nearctic and neotropical biotas overlap [L. halbingeriana and L. × oaxacana are distributed in the SMOR. However, Aragón-Parada et al. [L. crawshayana, L. furfuracea, and Laelia × meavei in their catalog of endemic vascular plants of the SMS, which partially coincides with our results. Some species such as L. eyermaniana and L. speciosa have extended their distribution to this province, contrary to what was reported by Halbinger and Soto-Arenas [Laelia species as micro-reserves. This is especially important when hotspots and endemism areas are located throughout heterogeneous environments such as the SMS and SMOR. At the same time, other species would be protected, as proposed by Salinas-Rodríguez et al. [Most of the taxa of  overlap ,66,67. T overlap ,69. Sala overlap  mention a et al.  recordedo-Arenas . Consequz et al.  and Aragz et al. .Laelia s.s., which had already been suggested by Halbinger and Soto-Arenas [Schomburgkia are distributed throughout the Isthmus, particularly S. anceps, S. rubescens, and S. superbiens. Large changes in the distribution patterns of many groups have been reported in this area [According to our results, the Isthmus of Tehuantepec seems to constitute an important geographical barrier for the genus o-Arenas . In addihis area ,71, and his area .Laelia species distributed in Mexico to the genus Schombugkia. Taking into account the previous morphological and phylogenetic evidence [Laelia s.s. is endemic to Mexico, which has important implications for conservation and management. Therefore, the conservation of Laelia s.s. should be prioritized if it is proven to be an endemic genus to Mexico.The results obtained from the climatic variables showed that the genera are statistically different in their environmental space, which together with the data on the distribution support the proposal by Peraza-Flores et al.  to transevidence , as wellLaelia gouldiana as ×Schombolaelia gouldiana according to Peraza-Flores et al. [L. gouldiana must be analyzed in depth, and we must establish whether or not it is a hybrid, as supported here. Accurately identifying plants is a huge challenge, even more so in organisms that we are interested in protecting. Hence, taxonomic changes can affect the conservation status of organisms, as emphasized in several studies [In addition, our statistical analyses also support the new combination for s et al. , which hs et al. . Soto-Ars et al.  had alre studies ,76,77,78Laelia populations are highly vulnerable, and studies should continue to be carried out to allow adequate measures to be taken for their correct management, as well as for the establishment of efficient strategies for their conservation. In this sense, the hotspots detected and the distribution and endemism patterns identified in this study should be used as references to establish and focus efforts on conservation in situ. In particular, the patterns described are important to define priority sites and areas for the conservation of these species, since among the attributes associated with the narrow geographical distribution are a local and global rarity, isolation, as well as functional diversity [Laelia and highlights the integrated importance of taxonomy, distribution patterns, and richness hotspots in diversity conservation.Although taxonomy and conservation are not the same, they do go hand in hand ,76,77,78iversity ,81,82. OLaelia in Mexico [https://www.gbif.org/ (accessed on 10 February 2022)), National Herbarium of Mexico (MEXU) (http://www.ib.unam.mx/botanica/herbario/ (accessed on 1 January 2022)), Network of Herbariums of Northwest Mexico ), SNIB-MX (http://www.snib.mx/ (accessed on 8 March 2022)), and Tropicos (www.tropicos.org (accessed on 10 March 2022)), as well as databases of herbaria such as CHAPA, CIB, CIIDIR, CITRO, CORU, EBUM, EAP, GBH, GUADA, HNMN, HUUA, LAGU, PMA, QMEX, SLPM, TEFH, UADY, UAS, WLM, XAL, and ZEA [® Excel v15.0. with the information collected.A preliminary list of species was compiled from an exhaustive review of the floristic–taxonomic literature on the genus n Mexico ,7,8,12.  and ZEA , the recwww.ipni.org (accessed on 12 April 2022)) and Plants of the World Online (http://powo.science.kew.org/ (accessed on 12 April 2022)). The risk statuses were consulted from the IUCN Red List [® Earth Pro v7.3  using the description of the collection location.The names of the species and their authors were verified on the web pages The International Plant Names Index  test was used, which is a measure of the receiver operating characteristic (ROC) analysis. According to Peterson et al. , models L. gouldina, a second PCA was carried out, integrating this species as a third group under the name of ×Schombolaelia gouldiana. In order to find out the differences between the three groups, a Tukey’s comparison of means was carried out. For both cases, a non-parametric post hoc analysis of similarities (ANOSIM) based on Euclidean distances was performed using all available variables and by applying the Bonferroni probability value (p) correction. All statistical analyses were carried out in RStudio v554.In order to explore differences in the environmental conditions in which the two putative genera inhabit, a principal component analysis (PCA) was carried out, taking into account the values of the 23 bioclimatic and topographic variables associated with each of the records of the different species. To determine the existence of significant differences between groups, the values of the most explanatory variables from the PCA were compared using an analysis of variance (ANOVA). To explore whether the abiotic variables contribute to clarifying the taxonomic status of