slotreck/pickle huggingface dataset:
The wound response of tomato plants has been extensively studied , and provides a useful model to understand signal transduction events leading from injury to marker gene expression . The principal markers that have been used in these studies are genes encoding proteinase inhibitor ( pin ) proteins . Activation of pin genes occurs in the wounded leaf and in distant unwounded leaves of the plant . This paper reviews current understanding of signalling pathways in the wounded leaf , and in the systemically responding unwounded leaves . First , the nature of known elicitors and their potential roles in planta are discussed , in particular , oligogalacturonides , jasmonates and the peptide signal , systemin . Inhibitors of wound-induced proteinase inhibitor ( pin ) expression are also reviewed , with particular reference to phenolics , sulphydryl reagents and fusicoccin . In each section , results obtained from the bioassay are considered within the wider context of data from mutants and from transgenic plants with altered levels of putative signalling components . Following this introduction , current models for pin gene regulation are described and discussed , together with a summary for the involvement of phosphorylation-dephosphorylation in wound signalling . Finally , a new model for wound-induced pin gene expression is presented , arising from recent data from the author 's laboratory .
Biosynthesis of nicotine in tobacco requires N-methylputrescine oxidase ( MPO ) , which belongs to the copper-containing amine oxidase superfamily . Previous studies identified tobacco MPO1 and its close homolog NtDAO1 ( formerly called MPO2 ) , of which MPO1 has been shown preferentially to oxidize N-methylated amines . We show here that NtDAO1 , as well as a homologous Arabidopsis diamine oxidase ( DAO ) , accept non-N-methylated amines more efficiently than their corresponding N-methylated amines . MPO1 is coordinately regulated with other nicotine biosynthesis genes with regard to COI1-MYC2-dependent jasmonate induction and its dependence on nicotine-specific ERF transcription factors , whereas NtDAO1 is constitutively expressed at low basal levels in tobacco plants . Both MPO1 and NtDAO1 are targeted to peroxisomes by their C-terminal motifs , and the peroxisomal localization of MPO1 is required for it to function in nicotine biosynthesis in jasmonate-elicited cultured tobacco cells . Restricted occurrence of the MPO subfamily in Nicotiana and Solanum indicates that , during the formation of the Solanaceae , MPO has evolved from a DAO , which functions in polyamine catabolism within peroxisomes , by optimizing substrate preference and gene expression patterns to be suitable for alkaloid formation .
Nodulation outer proteins secreted via type 3 secretion systems are involved in the process of symbiosis between legume plants and rhizobia . To study the function of NopT in symbiosis , we mutated nopT in Mesorhizobium amphore CCNWGS0123 ( GS0123 ) , which can nodulate black locust ( Robinia pseudoacacia ) . The nopT mutant induced higher levels of jasmonic acid , salicylic acid , and hydrogen peroxide accumulation in the roots of R. pseudoacacia compared with wild-type GS0123 . The ΔnopT mutant induced higher disease-resistant gene expression 72 hours post-inoculation ( hpi ) , whereas GS0123 induced higher disease-resistant gene expression earlier , at 36 hpi . Compared with the nopT mutant , GS0123 induced the up-regulation of most genes at 36 hpi and the down-regulation of most genes at 72 hpi . Proteolytically active NopT_GS0123 induced hypersensitive responses when expressed transiently in tobacco leaves ( Nicotiana benthamiana ) . Two NopT_GS0123 targets in R. pseudoacacia were identified , ATP-citrate synthase alpha chain protein 2 and hypersensitive-induced response protein . Their interactions with NopT_GS0123 triggered resistance by the plant immune system . In conclusion , NopT_GS0123 inhibited the host plant immune system and had minimal effect on nodulation in R. pseudoacacia . Our results reveal the underlying molecular mechanism of NopT function in plant-symbiont interactions .
The peduncle of water hyacinth ( Eichhornia crassipes ) showed the downward bending within 24 hours after full flowering . Previously it was suggested that the downward bending of peduncle might be induced by the differential growth of the epidermal cells of the portion because of the differential distribution of auxin in the upper side of the bending part of the peduncle . In order to investigate the effect of auxin and gravity on the peduncle bending in Water hyacinth , we examined the growth reaction of peduncle and the effects of plant hormones on the bending of peduncle under simulated microgravity , and the sedimentable amyloplast on earth and three dimensional (3D)-clinostat . As a result it was confirmed that the downward bending of peduncle in water hyacinth is the positive gravitropism , and that its phenomenon is caused by the differential distribution of auxin in the upper side of bending part of peduncle . It was found that the amyloplast sediments toward gravity direction in the bending part of the peduncle . From the present results , any direct relation between the sedimentable amyloplast and auxin transport were not cleared in the peduncle of water hyacinth . Further study should be carried out .
Precise floral transition from vegetative growth phase to reproductive growth phase is very important in plant life cycle . In flowering genetic pathways , DELLA proteins are master transcriptional regulators of gibberelic acid ( GA ) pathway , and FLOWERING LOCUS C ( FLC ) is a core repressor of vernalization pathway as well as downstream of DELLAs . As a crucial messenger in plants , the possible involvement of melatonin ( N-acetyl-5-methoxytryptamine ) in flowering and underlying molecular mechanism are unknown in Arabidopsis . In this study , we found that exogenous melatonin treatment delayed floral transition in Arabidopsis . Exogenous melatonin treatment conferred protein stabilizations of DELLAs [ REPRESSOR of ga1 - 3 ( RGA ) and RGA-LIKE3 ( RGL3 ) ] , without regulating the transcripts of DELLAs and endogenous GA level . Notably , exogenous melatonin delayed plant flowering and DELLA-activated transcripts of FLC were alleviated in della mutants , and those were exacerbated in DELLA overexpressing plants . Taken together , this study provides direct link between melatonin and floral transition , and indicates the novel involvement of DELLAs-activated FLC in melatonin-mediated flowering in Arabidopsis .
Leaf senescence is a complicated developmental process that involves degenerative changes and nutrient recycling . The progress of leaf senescence is controlled by various environmental cues and plant hormones , including ethylene , jasmonic acid , salicylic acid , abscisic acid , cytokinins , and strigolactones . The production of strigolactones is induced in response to nitrogen and phosphorous deficiency . Strigolactones also accelerate leaf senescence and regulate shoot branching and root architecture . Leaf senescence is actively promoted in a nutrient-poor soil environment , and nutrients are transported from old leaves to young tissues and seeds . Strigolactones might act as important signals in response to nutrient levels in the rhizosphere . In this review , we discuss the possible roles of strigolactones during leaf senescence .
It has been shown that indoleacetic acid ( IAA ) does not occur in developing grains of Hordeum vulgare L. ( barley ) , but that an unidentified indolic compound does . This compound , designated ' A ' , was also found to be a product of the metabolism of exogenous IAA by barley . The expression of the gibberellic acid effect was delayed for at least 8 h if grains were imbibed in a solution of IAA , and during this time , the IAA was metabolised . The enzyme system involved could be peroxidase , which was active in the grains at all stages of their development and at maturity , and partially purified extracts of peroxidase were found to have considerable IAA oxidase activity .
The plant-specific WUSCHEL-related homeobox ( WOX ) nuclear proteins have important roles in the transcriptional regulation of many developmental processes . Among the rice ( Oryza sativa ) WOX proteins , a loss of OsWOX3A function in narrow leaf2 ( nal2 ) nal3 double mutants ( termed nal2/3 ) causes pleiotropic effects , such as narrow and curly leaves , opened spikelets , narrow grains , more tillers , and fewer lateral roots , but almost normal plant height . To examine OsWOX3A function in more detail , transgenic rice overexpressing OsWOX3A ( OsWOX3A-OX ) were generated ; unexpectedly , all of them consistently exhibited severe dwarfism with very short and wide leaves , a phenotype that resembles that of gibberellic acid (GA)-deficient or GA-insensitive mutants . Exogenous GA3 treatment fully rescued the developmental defects of OsWOX3A-OX plants , suggesting that constitutive overexpression of OsWOX3A downregulates GA biosynthesis . Quantitative analysis of GA intermediates revealed significantly reduced levels of GA20 and bioactive GA1 in OsWOX3A-OX , possibly due to downregulation of the expression of KAO , which encodes ent-kaurenoic acid oxidase , a GA biosynthetic enzyme . Yeast one-hybrid and electrophoretic mobility shift assays revealed that OsWOX3A directly interacts with the KAO promoter . OsWOX3A expression is drastically and temporarily upregulated by GA3 and downregulated by paclobutrazol , a blocker of GA biosynthesis . These data indicate that OsWOX3A is a GA-responsive gene and functions in the negative feedback regulation of the GA biosynthetic pathway for GA homeostasis to maintain the threshold levels of endogenous GA intermediates throughout development .
Bisphenol A ( BPA ) is an endocrine disruptor that is ubiquitous in the environment . Previous studies have focused on the effects of BPA on plants to assess the ecological risk of BPA in the environment . To evaluate the effects of BPA on plant biological characters more systematically , we investigated the biological characters of above-ground and under-ground organs of soybean plants exposed to BPA . Meanwhile , the mechanisms for the observed changes were also analyzed from the view of hormone levels and photosynthesis . The results showed that after exposure to 0.8   mg   L(-1 ) BPA for three days , indole-3-acetic acid ( IAA ) and gibberellic acid levels in roots increased significantly , and the IAA level increased in leaves , so the character indices of roots and leaves both increased . The IAA and ethylene levels in stems increased , but the character indices of stems did not increased . With higher BPA concentrations , especially exposure to 17.2   mg   L(-1 ) BPA , the levels of IAA , gibberellic acid , and zeatin decreased ( except for the increased zeatin in leaves ) , and abscisic acid and ethylene levels increased ; thus , all of the character indices significantly decreased . By comparing the changes in various biological characters , we found that leaf area , root surface area , and root length changed most significantly . In addition , changes in photosynthetic parameters provided initial causes for plant growth changes , and impacted biological characters . The changes of character indices were stronger when the BPA exposure time was prolonged , and after the removal of BPA , the character indices showed some recovery . Therefore , BPA exposure can regulate the changes in plant characters by influencing hormone levels and photosynthesis , and root surface area , root length , and leaf area were the most sensitive to BPA .
NaCl alleviates Cd toxicity in Sesvium portulacastrum by maintaining plant water status and redox balance , protecting chloroplasts structure and inducing some potential Cd ( 2 + ) chelators as GSH and proline . It has been demonstrated that NaCl alleviates Cd-induced growth inhibition in the halophyte Sesuvium portulacastrum . However , the processes that mediate this effect are still unclear . In this work we combined physiological , biochemical and ultrastructural studies to highlight the effects of salt on the redox balance and photosynthesis in Cd-stressed plants . Seedlings were exposed to different Cd concentrations ( 0 , 25 and 50   µM Cd ) combined with low ( 0.09   mM ) ( LS ) , or high ( 200   mM ) NaCl ( HS ) in hydroponic culture . Plant-water relations , photosynthesis rate , leaf gas exchange , chlorophyll fluorescence , chloroplast ultrastructure , and proline and glutathione concentrations were analyzed after 1   month of treatment . In addition , the endogenous levels of stress-related hormones were determined in plants subjected to 25   µM Cd combined with both NaCl concentrations . In plants with low salt supply ( LS ) , Cd reduced growth , induced plant dehydration , disrupted chloroplast structure and functioning , decreased net CO2 assimilation rate ( A ) and transpiration rate ( E ) , inhibited the maximum potential quantum efficiency ( Fv/Fm ) and the quantum yield efficiency ( Φ PSII ) of PSII , and enhanced the non-photochemical quenching ( NPQ ) . The addition of 200   mM NaCl ( HS ) to the Cd-containing medium culture significantly mitigated Cd phytotoxicity . Hence , even at similar internal Cd concentrations , HS-Cd plants were less affected by Cd than LS-Cd ones . Hence , 200   mM NaCl significantly alleviates Cd-induced toxicity symptoms , growth inhibition , and photosynthesis disturbances . The cell ultrastructure was better preserved in HS-Cd plants but affected in LS-Cd plants . The HS-Cd plants showed also higher concentrations of reduced glutathione ( GSH ) , proline and jasmonic acid ( JA ) than the LS-Cd plants . However , under LS-Cd conditions , plants maintained higher concentration of salicylic acid ( SA ) and abscisic acid ( ABA ) than the HS-Cd ones . We conclude that in S. portulacastrum alleviation of Cd toxicity by NaCl is related to the modification of GSH and proline contents as well as stress hormone levels thus protecting redox balance and photosynthesis .
Understanding the interactions between drought and acute ozone ( O(3 ) ) stress in terms of signaling molecules and cell death would improve the predictions of plant responses to climate change . The aim was to investigate whether drought stress influences the responses of plants to acute episodes of O(3 ) exposure . In this study , the behavior of 84 Mediterranean evergreen Quercus ilex plants was evaluated in terms of cross-talk responses among signaling molecules . Half of the sample was subjected to drought ( 20 % of the effective daily evapotranspiration , for 15 days ) and was later exposed to an acute O(3 ) exposure ( 200 nL L(-1 ) for 5 h ) . First , our results indicate that in well-water conditions , O(3 ) induced a signaling pathway specific to O(3)-sensitive behavior . Second , different trends and consequently different roles of phytohormones and signaling molecules ( ethylene , ET ; abscisic acid , ABA ; salycilic acid , SA and jasmonic acid , JA ) were observed in relation to water stress and O(3 ) . A spatial and functional correlation between these signaling molecules was observed in modulating O(3)-induced responses in well-watered plants . In contrast , in drought-stressed plants , these compounds were not involved either in O(3)-induced signaling mechanisms or in leaf senescence ( a response observed in water-stressed plants before the O(3)-exposure ) . Third , these differences were ascribable to the fact that in drought conditions , most defense processes induced by O(3 ) were compromised and/or altered . Our results highlight how Q. ilex plants suffering from water deprivation respond differently to an acute O(3 ) episode compared to well-watered plants , and suggest new effect to be considered in plant responses to environmental changes . This poses the serious question as to whether or not multiple high-magnitude O(3 ) events ( as predicted ) can change these cross-talk responses , thus opening it up possible further investigations .
KEY MESSAGE : Arabidopsis gulliver3 - D/dwarf4 - D displays growth-promoting phenotypes due to activation tagging of a key brassinosteroid biosynthetic gene DWARF4 . In gul3-D/dwf4-D , the Jasmonate and Salicylate signaling pathways were relatively activated and suppressed , respectively . Energy allocation between growth and defense is elegantly balanced to achieve optimal development in plants . Brassinosteroids ( BRs ) , steroidal hormones essential for plant growth , are regulated by other plant hormones , including auxin and jasmonates ( JA ) ; auxin stimulates the expression of a key brassinosteroid ( BR ) biosynthetic gene , DWARF4 ( DWF4 ) , whereas JA represses it . To better understand the interaction mechanisms between growth and defense , we isolated a fast-growing mutant , gulliver3-D ( gul3-D ) , that resulted from the activation tagging of DWF4 , and examined the response of this mutant to defense signals , including JA , Pseudomonas syringae pv . tomato ( Pst DC3000 ) infection , and wounding . The degree of root growth inhibition following MeJA treatment was significantly decreased in gul3 - 1D/dwf4 - 5D relative to the wild type , suggesting that JA signaling is partially desensitized in gul3 - 1D . Quantitative RT-PCR analysis of the genes involved in JA and salicylic acid ( SA ) responses , including MYC2 , PDF1.2 , CORI3 , PR1 , and PR2 , revealed that JA signaling was preferentially activated in gul3 - 1D , whereas SA signaling was suppressed . As a result , gul3 - 1D was more susceptible to a biotrophic pathogen , Pst DC3000 . Based on our results , we propose a model in which BR and JA cooperate to balance energy allocation between growth and defense responses . In ambient conditions , BRs promote plant growth ; however , when stresses trigger JA signaling , JA compromises BR signaling by downregulating DWF4 expression .
Bacterial wilt caused by the bacterial pathogen Ralstonia solanacearum is one of the most devastating crop diseases worldwide . The molecular mechanisms controlling the early stage of R. solanacearum colonization in the root remain unknown . Aiming to better understand the mechanism of the establishment of R. solanacearum infection in root , we established four stages in the early interaction of the pathogen with Arabidopsis roots and determined the transcriptional profiles of these stages of infection . A total 2,698 genes were identified as differentially expressed genes during the initial 96 h after infection , with the majority of changes in gene expression occurring after pathogen-triggered root-hair development observed . Further analysis of differentially expressed genes indicated sequential activation of multiple hormone signaling cascades , including abscisic acid ( ABA ) , auxin , jasmonic acid , and ethylene . Simultaneous impairment of ABA receptor genes promoted plant wilting symptoms after R. solanacearum infection but did not affect primary root growth inhibition or root-hair and lateral root formation caused by R. solanacearum . This indicated that ABA signaling positively regulates root defense to R. solanacearum . Moreover , transcriptional changes of genes involved in primary root , lateral root , and root-hair formation exhibited high temporal dynamics upon infection . Taken together , our results suggest that successful infection of R. solanacearum on roots is a highly programmed process involving in hormone crosstalk .
Gibberellic acid ( GA ) regulates many aspects of plant growth and development . The DELLA proteins act to restrain plant growth , and GA relieves this repression by promoting their degradation via the 26S proteasome pathway . The elucidation of the crystalline structure of the GA soluble receptor GID1 protein represents an important breakthrough for understanding the way in which GA is perceived and how it induces the destabilization of the DELLA proteins . Recent advances have revealed that the DELLA proteins are involved in protein-protein interactions within various environmental and hormone signaling pathways . In this review , we highlight our current understanding of the ' relief of repression ' model that aims to explain the role of GA and the function of the DELLA proteins , incorporating the many aspects of cross-talk shown to exist in the control of plant development and the response to stress .
Oxophytodienoate reductases ( OPRs ) are a small group of flavin-dependent oxidoreductases in plants . In this study , a new member of the OPR gene family ( HvOPR2 ) was cloned from barley ( Hordeum vulgare L. ) using reverse transcription polymerase chain reaction ( RT-PCR ) . The full-length cDNA of HvOPR2 was 1,206 bp with an open reading frame of 1,101 bp , encoding a 366 amino acids long polypeptide with a predicted molecular weight of 40.52 and a theoretical isoelectric point of 6.21 . The corresponding genomic clone of HvOPR2 was isolated using the PCR amplification technique and was found to consist of five exons and four introns . Bioinformatic analysis revealed that the deduced HvOPR2 has a considerable homology with other plant OPRs and possessed the flavin oxidoreductase/NADH oxidase substrate-binding domain . Phylogenetic analysis showed that HvOPR2 codes for the OPR of subgroup I , which contains enzymes that are not required for jasmonic acid biosynthesis . Time-course transcriptional profiling of HvOPR2 was analyzed in response to a variety of abiotic stresses and hormonal treatments by semi-quantitative RT-PCR . The HvOPR2 gene was induced in response to drought , hydrogen peroxide , and wounding . Moreover , the corresponding mRNA transcripts were increased in response to jasmonic acid and salicylic acid , but not in response to abscisic acid . These results strongly suggested a role for HvOPR2 in barley defense/response to abiotic stresses and signaling molecules .
The phytoalexin-deficient Arabidopsis mutant pad3 - 1 , which is affected in the production of the indole-type phytoalexin camalexin , has previously been shown not to display altered susceptibility to either the bacterium Pseudomonas syringae ( Glazebrook & Ausubel 1994 ; Proc . Natl . Acad . Sci . USA , 91 : 8955 - 8959 ) or the biotrophic fungi Peronospora parasitica ( Glazebrook et al. 1997 ; Genetics , 146 : 381 - 392 ) and Erysiphe orontii ( Reuber et al. 1998 ; Plant J. 16 : 473 - 485 ) . We now show that this mutant is markedly more susceptible than its wild-type parental line to infection by the necrotrophic fungus Alternaria brassicicola , but not to Botrytis cinerea . A strong camalexin response was elicited in wild-type plants inoculated with either Alternaria brassicicola or Botrytis cinerea , whereas no camalexin could be detected in pad3 - 1 challenged with these fungi . Hence , PAD3 appears to be a key determinant in resistance to at least A. brassicicola . The induction of salicylate-dependent and jasmonate/ethylene-dependent defense genes was not reduced in Alternaria-challenged pad3 - 1 plants compared to similarly treated wild-type plants . Camalexin production could not be triggered by exogenous application of either salicylate , ethylene or jasmonate and was not , or not strongly , reduced in mutants with defects in perception of these defense-related signal molecules . Camalexin-production appears to be controlled by a pathway that exhibits little cross-talk with salicylate- , ethylene- and jasmonate-dependent signalling events .