slotreck/pickle huggingface dataset:
Reducing phenylpropanoid biosynthesis in transgenic tobacco compromises systemic acquired resistance ( SAR ) to tobacco mosaic virus , while increasing phenylpropanoid biosynthesis enhances SAR . Surprisingly , transgenic tobacco plants compromised in SAR exhibit more effective grazing-induced systemic resistance to larvae of Heliothis virescens , whereas induced insect resistance is compromised in transgenic plants with elevated phenylpropanoid levels . Levels of the phenylpropanoid-derived signal salicylic acid are directly correlated with overall phenylpropanoid biosynthesis in this series of transgenic plants . Moreover , while pathogen-induced SAR is almost completely compromised in salicylic acid-deficient plants expressing the bacterial nahG salicylate hydroxylase gene , these plants show enhanced grazing-induced insect resistance compared to wild-type . Hence , suppression of grazing-induced insect resistance is mediated at least in part by salicylic acid and likely reflects salicylic acid inhibition of the synthesis and action of the wound signal jasmonic acid . We propose that the dual functions of salicylic acid contribute to a signal poise which constrains constitutive expression of disease and insect resistance mechanisms , and reciprocally switches their selective activation .
Plants sense and respond to microbes utilizing a multilayered signalling cascade . In seed plants , the phytohormones jasmonic and salicylic acid ( JA and SA ) are key denominators of how plants respond to certain microbes . Their interplay is especially well-known for tipping the scales in plants ' strategies of dealing with phytopathogens . In non-angiosperm lineages , the interplay is less well understood , but current data indicate that it is intertwined to a lesser extent and the canonical JA/SA antagonism appears to be absent . Here , we used the water fern Azolla filiculoides to gain insights into the fern 's JA/SA signalling and the molecular communication with its unique nitrogen fixing cyanobiont Nostoc azollae , which the fern inherits both during sexual and vegetative reproduction . By mining large-scale sequencing data , we demonstrate that Azolla has most of the   genetic repertoire to produce and sense JA and SA . Using qRT-PCR on the identified biosynthesis and signalling marker genes , we show that Azolla is responsive to exogenously applied SA . Furthermore , exogenous SA application influenced the abundance and gene expression of Azolla 's cyanobiont . Our data provide a framework for JA/SA signalling in ferns and suggest that SA might be involved in Azolla 's communication with its vertically inherited cyanobiont .
Plants counteract attack by herbivorous insects using a variety of inducible defence mechanisms . The production of toxic proteins and metabolites that instantly affect the herbivore 's development are examples of direct induced defence . In addition , plants may release mixtures of volatile organic compounds ( VOCs ) that indirectly protect the plant by attracting natural enemies of the herbivore . Recent studies suggest that these VOCs can also prime nearby plants for enhanced induction of defence upon future insect attack . However , evidence that this defence priming causes reduced vulnerability to insects is sparse . Here we present molecular , chemical and behavioural evidence that VOC-induced priming leads to improved direct and indirect resistance in maize . A differential hybridization screen for inducible genes upon attack by Spodoptera littoralis caterpillars identified 10 defence-related genes that are responsive to wounding , jasmonic acid ( JA ) , or caterpillar regurgitant . Exposure to VOCs from caterpillar-infested plants did not activate these genes directly , but primed a subset of them for earlier and/or stronger induction upon subsequent defence elicitation . This priming for defence-related gene expression correlated with reduced caterpillar feeding and development . Furthermore , exposure to caterpillar-induced VOCs primed for enhanced emissions of aromatic and terpenoid compounds . At the peak of this VOC emission , primed plants were significantly more attractive to parasitic Cotesia marginiventris waSPS . This study shows that VOC-induced priming targets a specific subset of JA-inducible genes , and links these responses at the molecular level to enhanced levels of direct and indirect resistance against insect attack .
Inducible anti-herbivore defenses in plants are predominantly regulated by jasmonic acid ( JA ) . On tomato plants , most genotypes of the herbivorous generalist spider mite Tetranychus urticae induce JA defenses and perform poorly on it , whereas the Solanaceae specialist Tetranychus evansi , who suppresses JA defenses , performs well on it . We asked to which extent these spider mites and the predatory mite Phytoseiulus longipes preying on these spider mites eggs are affected by induced JA-defenses . By artificially inducing the JA-response of the tomato JA-biosynthesis mutant def-1 using exogenous JA and isoleucine ( Ile ) , we first established the relationship between endogenous JA-Ile-levels and the reproductive performance of spider mites . For both mite species we observed that they produced more eggs when levels of JA-Ile were low . Subsequently , we allowed predatory mites to prey on spider mite-eggs derived from wild-type tomato plants , def-1 and JA-Ile-treated def-1 and observed that they preferred , and consumed more , eggs produced on tomato plants with weak JA defenses . However , predatory mite oviposition was similar across treatments . Our results show that induced JA-responses negatively affect spider mite performance , but positively affect the survival of their offspring by constraining egg-predation .
Jasmonic acid and its derived metabolites ( JAs ) orchestrate plant defense against insects and fungi . 12-Oxo-phytodienoic acid ( OPDA ) , a JA precursor , has also been implicated in plant defense . We sought to define JAs and OPDA functions through comparative defense susceptibility characteristics of three Arabidopsis ( Arabidopsis thaliana ) genotypes : aos , lacking JAs and OPDA ; opda reductase3 ( opr3 ) , deficient in JA production but can accumulate OPDA ; and transgenics that overexpress OPR3 . opr3 , like aos , is susceptible to cabbage loopers ( Trichoplusia ni ) but , relative to aos , opr3 has enhanced resistance to a necrotrophic fungus . Gas chromatography-mass spectrometry reveals that opr3 produces OPDA but no detectable JAs following wounding and looper infestation ; unexpectedly , substantial levels of JAs accumulate in opr3 upon fungal infection . Full-length OPR3 transcripts accumulate in fungal-infected opr3 , potentially through splicing of the T-DNA containing intron . Fungal resistance correlates with levels of JAs not OPDA ; therefore , opr3 resistance to some pests is likely due to JA accumulation , and signaling activities ascribed to OPDA should be reassessed because opr3 can produce JAs . Together these data ( 1 ) reinforce the primary role JAs play in plant defense against insects and necrotrophic fungi , ( 2 ) argue for a reassessment of signaling activities ascribed to OPDA , and ( 3 ) provide evidence that mutants with intron insertions can retain gene function .
The plant-signaling molecules salicylic acid ( SA ) and jasmonic acid ( JA ) play an important role in induced disease resistance pathways . Cross-talk between SA- and JA-dependent pathways can result in inhibition of JA-mediated defense responses . We investigated possible antagonistic interactions between the SA-dependent systemic acquired resistance ( SAR ) pathway , which is induced upon pathogen infection , and the JA-dependent induced systemic resistance ( ISR ) pathway , which is triggered by nonpathogenic Pseudomonas rhizobacteria . In Arabidopsis thaliana , SAR and ISR are effective against a broad spectrum of pathogens , including the foliar pathogen Pseudomonas syringae pv . tomato ( Pst ) . Simultaneous activation of SAR and ISR resulted in an additive effect on the level of induced protection against Pst . In Arabidopsis genotypes that are blocked in either SAR or ISR , this additive effect was not evident . Moreover , induction of ISR did not affect the expression of the SAR marker gene PR-1 in plants expressing SAR . Together , these observations demonstrate that the SAR and the ISR pathway are compatible and that there is no significant cross-talk between these pathways . SAR and ISR both require the key regulatory protein NPR1 . Plants expressing both types of induced resistance did not show elevated Npr1 transcript levels , indicating that the constitutive level of NPR1 is sufficient to facilitate simultaneous expression of SAR and ISR . These results suggest that the enhanced level of protection is established through parallel activation of complementary , NPR1-dependent defense responses that are both active against Pst . Therefore , combining SAR and ISR provides an attractive tool for the improvement of disease control .
High-frequency bud break and multiple shoots were induced in apical shoot buds and nodal explants ofMorus cathayana , M. lhou andM. serrata on Murashige and Skoog ( MS ) medium containing 0.5 - 1.0 mg/l 6-benzylaminopurine ( BAP ) . Addition of gibberellic acid ( 0.4 mg/l ) along with BAP induced faster bud break both in apical shoot buds and nodal explants and also enhanced the frequency of bud break in all three species . Shoot culture initiation was greatly influenced by explant type , explant age and explanting season . The shoots were successfully rooted on half-strength MS medium containing a combination of indole-3-acetic acid , indole-3-butyric acid and indole-3-propionic acid , each at 1.0 mg/l . The plantlets were successfully acclimated and eventually established in soil .
In tobacco ( Nicotiana tabacum ) , nicotine is the predominant alkaloid . It is produced in the roots and accumulated mainly in the leaves . Jasmonates play a central signaling role in damage-induced nicotine formation . The genome sequence of tobacco provides us an almost complete inventory of structural and regulatory genes involved in nicotine pathway . Phylogenetic and expression analyses revealed a series of structural genes of the nicotine pathway , forming a regulon , under the control of jasmonate-responsive ETHYLENE RESPONSE FACTOR ( ERF ) transcription factors . The duplication of NAD and polyamine metabolic pathways and the subsequent recruitment of duplicated primary metabolic genes into the nicotine biosynthesis regulon were suggested to be the drivers for pyridine and pyrrolidine ring formation steps early in the pathway . Transcriptional regulation by ERF and cooperatively acting MYC2 transcription factors are corroborated by the frequent occurrence of cognate cis-regulatory elements of the factors in the promoter regions of the downstream structural genes . The allotetraploid tobacco has homologous clusters of ERF genes on different chromosomes , which are possibly derived from two ancestral diploids and include either nicotine-controlling ERF189 or ERF199 A large chromosomal deletion was found within one allele of the nicotine-controlling NICOTINE2 locus , which is part of one of the ERF gene clusters , and which has been used to breed tobacco cultivars with a low-nicotine content .
A novel method based on off-line membrane-supported liquid-liquid-liquid microextraction ( MS-LLLME ) combined with on-column anion-selective exhaustive injection ( ASEI ) capillary electrophoresis-ultraviolet ( CE-UV ) detection was established for the analysis of seven phytohormones ( abscisic acid ( ABA ) , jasmonic acid ( JA ) , 2,4-dichlorophenoxyacetic acid ( 2,4-D ) , 1-naphthalene acetic acid ( NAA ) , indole-3-acetic acid ( IAA ) , salicylic acid ( SA ) and gibberellic acid ( GA ) ) . In MS-LLLME , the target phytohormones were extracted from the acid donor phase to the alkaline acceptor phase , and the acceptor solutions were directly analyzed by ASEI-CE-UV . Under the optimal experimental conditions , the analytical performance of the method was evaluated . The limits of detection ( LODs ) of ABA , JA , 2,4-D , NAA , IAA , SA and GA were determined to be 1.00 , 2.21 , 0.33 , 0.17 , 0.67 , 0.05 and 16.5ng/mL , respectively . The relative standard deviations ( RSDs , n=7 ) ranged from 4.7 % to 12.9 % , and the enrichment factors were in the range of 307 to 20,160 . The proposed method was successfully applied for the determination of multiple phytohormones in banana , cabbage and cucumber extracts , and ABA , IAA and SA were detected in these samples . The recoveries for the spiked samples were in the range of 79.0 to 116.4 % . The proposed method was demonstrated to be suitable for the simultaneous quantification of multiple phytohormones with high sensitivity and good sample cleanup ability .
The ability to adjust growth and development to the availability of mineral nutrients in the soil is an essential life skill of plants but the underlying signaling pathways are poorly understood . In Arabidopsis thaliana , shortage of potassium ( K ) induces a number of genes related to the phytohormone jasmonic acid ( JA ) . Using comparative microarray analysis of wild-type and coi1 - 16 mutant plants , we classified transcriptional responses to K with respect to their dependence on COI1 , a central component of oxylipin signaling . Expression profiles obtained in a short-term experiment clearly distinguished between COI1-dependent and COI1-independent K-responsive genes , and identified both known and novel targets of JA-COI1-signaling . During long-term K-deficiency , coi-16 mutants displayed de novo responses covering similar functions as COI1-targets except for defense . A putative role of JA for enhancing the defense potential of K-deficient plants was further supported by the observation that plants grown on low K were less damaged by thrips than plants grown with sufficient K.
The Arabidopsis Jasmonate ZIM-domain proteins ( JAZs ) act as substrates of SCF(COI1 ) complex to repress their downstream targets , which are essential for JA-regulated plant development and defense . The bHLH transcription factor MYC2 was found to interact with JAZs and mediate JA responses including JA-inhibitory root growth . Here , we identified another bHLH transcription factor MYC3 which directly interacted with JAZs by virtue of its N-terminal region to regulate JA responses . The transgenic plants with overexpression of MYC3 exhibited hypersensitivity in JA-inhibitory root elongation and seedling development . The JAZ-interacting pattern and the JA-induced expression pattern of MYC3 were distinguishable from those of MYC2 . We speculate that MYC3 and MYC2 may have redundant but also distinguishable functions in regulation of JA responses .
Health effects of subacute treatment of combinations of gibberellic acid and ethephon ( 2-chloroethylphosphonic acid ) were investigated . Mice was used as an experimental model . Ten groups of male ICR ( CD-1 ) mice were treated with oral doses of 25 , 50 and 100 mg of either gibberellic acid ( GA3 ) , ethephon ( 2-chloroethylphosphonic acid ) alone or in combination / kg body weight for 11 weeks . A significant dose dependent reduction in weight gain and low dry matter intakes were recorded in animals treated with the combination of both chemicals . Treated groups showed statistically significant increases in mean liver , kidney and spleen weights . Hemoglobin ( Hb ) and total erythrocyte count ( TEC ) decreased while total leukocyte count ( TLC ) was raised in all treated groups . Gibberellic acid ( alone ) treated animals showed the highest activity of liver aspartate aminotransferase ( AST ) while no significant variations were recorded among other groups . No significant differences were recorded in the activity of hepatic alanine aminotransferase ( ALT ) . A highly significant variation was recorded among the three treatments in serum urea level . No significant difference was noted among the three treatments in serum creatinine . All treatments caused significant dose dependent increases in creatinine than that of the control group . A highly significant dose dependent variation occurred in acetyl choline esterase ( AChE ) activity among treated groups . Groups treated with ethephon alone showed the greatest inhibition in brain AChE.
The cytokinin activity has been isolated and identified from extracts of immature mango ( Mangifera indica L. ) seeds . The structures of zeatin , zeatin riboside , and N(6)-(Delta(2)-isopentenyl)adenine riboside were confirmed on the basis of their chromatographic behavior and mass spectra of trimethylsilyl derivatives . Both trans and cis isomers of zeatin and zeatin riboside were also identified by the retention times of high performance liquid chromatography . In addition , an unidentified compound appeared to be a cytokinin glucoside . The concentration of cytokinins in the panicle and pulp of mango reached a maximum 5 to 10 days after full bloom and decreased rapidly thereafter . The cytokinin level in the seed remained high until the 28th day after full bloom . The quantity of cytokinins in pulp per fruit increased from the 10th day after full bloom , the maximum being attained around the 50th day after full bloom . Similarly , the amount of cytokinins per seed increased from the 10th day after full bloom , reaching a peak on the 40th day and decreasing gradually thereafter . A high percentage of fruit set in mango was persistently maintained by supplying 6-benzylaminopurine ( 1.5 x 10(3 ) micromolar ) onto the panicle at the anthesis stage and by supplying gibberellic acid ( 7.2 x 10(2 ) micromolar ) and naphthalene acetamide ( 3.1 x 10 micromolar ) at the young fruit stage .
Gibberellin ( GA ) , a diterpene hormone , plays diverse roles in plant growth and development , including seed germination , stem elongation , and flowering time . Although it is known that GA accelerates flowering through degradation of transcription repressors , DELLAs , the underlying mechanism is poorly understood . We show here that DELLA directly binds to microRNA156 (miR156)-targeted SQUAMOSA PROMOTER BINDING-LIKE ( SPL ) transcription factors , which promote flowering by activating miR172 and MADS box genes . The interaction between DELLA and SPL interferes with SPL transcriptional activity and consequently delays floral transition through inactivating miR172 in leaves and MADS box genes at shoot apex under long-day conditions or through repressing MADS box genes at the shoot apex under short-day conditions . Our results elucidate the molecular mechanism by which GA controls flowering and provide the missing link between DELLA and MADS box genes .
Gibberellic acid ( GA(3 ) ) promotes and continuous gold light inhibits germination of seeds of a dwarf strain ( WB-2 ) of watermelon [ Citrullus lanatus ( Thunb . ) Matsu . and Nakai ] . Osmotic inhibition of germination with mannitol in light-grown seeds of WB-2 was only slightly reversed by GA(3 ) at the concentrations used , whereas , GA(3 ) substantially relieved osmotic inhibition in dark-grown seeds . The effects of GA(3 ) and gold light on development of catalase and invertase activities and on levels of free amino acids in germinating seeds of WB-2 were examined . Light depressed development of catalase and invertase activity . Levels of free amino acids increased more slowly in embryonic axes of light- than dark-incubated seeds , but in cotyledons higher levels of amino acids were maintained in light-grown seeds . GA(3 ) accelerated the development of catalase activity in whole embryos and invertase activity in embryonic axes , but did not significantly affect invertase activity in cotyledons during germination . GA(3 ) had little effect on amino acid pools in cotyledons and embryonic axes .
Plant growth and development are controlled by nine structurally distinct small molecules termed phytohormones . Over the last 20 years , the molecular basis of their signal transduction , from receptors to transcription factors , has been dissected using mainly Arabidopsis thaliana and rice as model systems . Phytohormones can be broadly classified into two distinct groups on the basis of whether the subcellular localization of their receptors is in the cytoplasm or nucleus , and hence soluble , or membrane-bound , and hence insoluble . Soluble receptors , which control the responses to auxin , jasmonates , gibberellins , strigolactones and salicylic acid , signal either directly or indirectly via the destruction of regulatory proteins . Responses to abscisic acid are primarily mediated by soluble receptors that indirectly regulate the phosphorylation of targeted proteins . Insoluble receptors , which control the responses to cytokinins , brassinosteroids and ethylene , transduce their signal through protein phosphorylation . This chapter provides a comparison of the different components of these signalling systems , and discusses the similarities and differences between them .
High temperature ( HT ) , high humidity ( HH ) , and pathogen infection often co-occur and negatively affect plant growth . However , these stress factors and plant responses are generally studied in isolation . The mechanisms of synergistic responses to combined stresses are poorly understood . We isolated the subgroup IIb WRKY family member CaWRKY6 from Capsicum annuum and performed quantitative real-time PCR analysis . CaWRKY6 expression was upregulated by individual or simultaneous treatment with HT , HH , combined HT and HH ( HTHH ) , and Ralstonia solanacearum inoculation , and responded to exogenous application of jasmonic acid ( JA ) , ethephon , and abscisic acid ( ABA ) . Virus-induced gene silencing of CaWRKY6 enhanced pepper plant susceptibility to R. solanacearum and HTHH , and downregulated the hypersensitive response ( HR ) , JA- , ethylene (ET)- , and ABA-induced marker gene expression , and thermotolerance-associated expression of CaHSP24 , ER-small CaSHP , and Chl-small CaHSP . CaWRKY6 overexpression in pepper attenuated the HTHH-induced suppression of resistance to R. solanacearum infection . CaWRKY6 bound to and activated the CaWRKY40 promoter in planta , which is a pepper WRKY that regulates heat-stress tolerance and R. solanacearum resistance . CaWRKY40 silencing significantly blocked HR-induced cell death and reduced transcriptional expression of CaWRKY40 . These data suggest that CaWRKY6 is a positive regulator of R. solanacearum resistance and heat-stress tolerance , which occurs in part by activating CaWRKY40 .
Jasmonates are essential engineers of plant defense responses against many pests , including herbivorous insects . Herbivory induces the production of jasmonic acid ( JA ) and its bioactive conjugate jasmonoyl-L-isoleucine ( JA-Ile ) , which then triggers a large transcriptional reprogramming to promote plant acclimation . The contribution of the JA pathway , including its components and regulators , to defense responses against insect herbivory can be evaluated by conducting bioassays with a wide range of host plants and insect pests . Here , we describe a detailed and reproducible protocol for testing feeding behavior of the generalist herbivore Spodoptera littoralis on the model plant Arabidopsis thaliana and hence infer the contribution of JA-mediated plant defense responses to a chewing insect .