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PROVIDER: PRJNA853395 | ENA |
REPOSITORIES: ENA
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Project description:Leaf senescence is a highly coordinated and complicated process with the integration of numerous internal and environmental signals. Salicylic acid (SA) and reactive oxygen species (ROS) are two well-defined inducers of leaf senescence, whose contents progressively and inter-dependently increase during leaf senescence via a yet unknown mechanism. Here, we have characterized a newly identified positive regulator of leaf senescence, WRKY75, and demonstrated that knock-down or knock-out of WRKY75 delays, while over-expression of WRKY75 accelerates age-dependent leaf senescence. The WRKY75 transcription is induced by age, SA, H2O2, as well as multiple plant hormones. Meanwhile, WRKY75 is able to promote SA production by inducing the transcription of SA INDUCTION-DEFICIENT 2 (SID2), and suppress H2O2 scavenging partly by repressing the transcription of CATALASE 2 (CAT2). Genetic analysis reveals that the SID2 mutation or an increase of catalase activity rescues the precocious leaf senescence phenotype evoked by WRKY75 over-expression. Based on these results, we propose a “tripartite amplification loop” model in which WRKY75, SA and ROS undergo a gradual but self-sustained rise driven by three interlinked positive feedback regulations. This tripartite amplification loop provides a molecular framework connecting the upstream signals, such as age, ethylene, JA and ABA, to the downstream regulatory network executed by those SA-responsive and H2O2-responsive transcription factors during leaf senescence.
2017-11-07 | GSE102302 | GEO
Project description:Leaf senescence is a developmental process designed for nutrient recycling and relocation to maximize growth competence and reproductive capacity of plants. Thus, plants integrate developmental and environmental signals to precisely control senescence. However, it remains largely elusive as to how plants coordinate genetic, epigenetic, and metabolic pathways for the regulation of senescence. To genetically dissect the complex regulatory mechanism underlying leaf senescence, we identified an early leaf senescence mutant, rse1. RSE1 encodes a putative glycosyltranferase. Loss-of-function mutations in RSE1 resulted in precocious leaf yellowing and up-regulation of senescence maker genes, indicating enhanced leaf senescence. Transcriptome analysis revealed that salicylic acid (SA) and defense signaling cascades were activated in rse1 prior to the onset of leaf senescence. In agreement with the phenotypes, we found that SA accumulation was significantly increased in rse1. We also discovered that the rse1 phenotypes are dependent on SA-INDUCTION DEFICIENT 2 (SID2), indicating a role of SA in accelerated leaf senescence in rse1. Furthermore, RSE1 protein was localized to the cell walls, and rse1 displayed increased glucose contents in the cell walls, implying a possible link between the cell walls and RSE1 function. Together, we show that RSE1 negatively modulate leaf senescence through an SID2-dependent SA signaling pathway.
2019-10-18 | GSE132740 | GEO
Project description:Leaf senescence can be triggered by jasmonic acid (JA) and darkness. There are scattered reports about JA and dark-induced senescence, respectively. While the precise regulatory mechanisms that integrate these two factors to initiate and regulate leaf senescence have not been identified. Here, we report a transcriptional regulating module centered on novel WRKY transcription factor that is responsible for both JA and dark-induced leaf senescence in tomato. The expression levels of SlWRKY37 together with the master transcription factor in JA signaling SlMYC2 could be significantly induced by both MeJA and dark treatments. SlMYC2 directly binds to the promoter of SlWRKY37 to active its expression. Knock out of SlWRKY37 inhibited JA and dark-induced leaf senescence. Transcriptome analysis revealed 1312 differentially expressed genes between slwrky37-CR and SlWRKY37-OE, including genes involved in JA synthesis as well as several senescence-associated genes (SAGs). We characterized SlWRKY53 and SlSGR1 as direct transcriptional targets of SlWRKY37 to regulate leaf senescence. Moreover, SlWRKY37 interacts with SlVQ7 protein in vivo and the interaction enhances its binding ability to the promoters and transcriptional activation to downstream target genes. In addition, SlWRKY37 is phosphorylated at the post-translational level. Phosphorylation of SlWRKY37 is essential for its protein interaction and transcriptional activation, indicating phosphorylation modification has a great effect on the function of SlWRKY37 protein. Our study reveals the physiological and molecular functions of SlWRKY37 in leaf senescence and offered a target gene to retard leaf yellowing by reducing the sensitivity to internal and external senescence signal such as JA and darkness.
2022-06-01 | GSE186072 | GEO
Project description:Enhancing grain production of rice (Oryza sativa L.) is a top priority in ensuring food security for human being. One approach to increase yield is to delay leaf senescence and to extend the available time for photosynthesis. microRNAs (miRNAs) are key regulators for aging and cellular senescence in eukayotes. However, miRNAs and their roles in rice leaf senescence remain unexplored. Here, we report identification of miRNAs and their putative target genes by deep sequencing of six small RNA libraries, six RNA-seq libraries and two degradome libraries from the leaves of two super hybrid rice, Nei-2-You 6 (N2Y6, age-resistant rice) and Liang-You-Pei 9 (LYP9, age-sensitive rice). Totally 372 known miRNAs and 162 miRNA candidates were identified, and 1145 targets were identified. Compared with the expression of miRNAs in the leaves of LYP9, the numbers of miRNAs up-regulated and down-regulated in the leaves of N2Y6 were 47 and 30 at early stage of grain-filling, 21 and 17 at the middle stage, and 11 and 37 at the late stage, respectively. Six miRNA families, osa-miR159, osa-miR160 osa-miR164, osa-miR167, osa-miR172 and osa-miR1848, targeting the genes encoding APETALA2 (AP2), zinc finger proteins, salicylic acid-induced protein 19 (SIP19), Auxin response factors (ARF) and NAC transcription factors, respectively, were found to be involved in leaf senescence through phytohormone signaling pathways. These results provided valuable information for understanding the miRNA-mediated leaf senescence of rice, and offered an important foundation for rice breeding.
2015-01-01 | GSE62200 | GEO
Project description:We conducted the combination analysis of transcriptomic and epigenomic data between kaku4-2 mutant and WT suggested that KAKU4 may inhibit the expression of a series of genes related to hormone signals and H2O2 metabolism by affecting the deposition of H3K27me3, thereby suppressing leaf senescence.
2024-02-09 | GSE250299 | GEO
Project description:As maize (Zea mays) plants undergo vegetative phase change from juvenile to adult, they both exhibit heteroblasty, an abrupt change in patterns of leaf morphogenesis, and gain the ability to produce flowers. Both processes are under the control of microRNA 156, whose levels decline at the end of the juvenile phase. Gain of ability to flower is conferred by expression of miR156 targets that encode Squamosa Promoter-Binding (SBP) transcription factors, which when derepressed in the adult phase induce the expression of MADS-box transcription factors that promote maturation and flowering. What gene expression differences underlie heteroblasty, as well as what regulates miR156 levels, remain open questions. Here, we compare gene expression in primordia that will develop into juvenile or adult leaves to identify genes that define these two developmental states and may influence vegetative phase change. In comparisons among successive leaves at the same developmental stage of plastochron 6, three-fourths of approximately 1,100 differentially expressed genes were more highly expressed in primordia of juvenile leaves. This juvenile set was enriched in photosynthetic genes, particularly those associated with cyclic electron flow at photosystem I, and in genes involved in oxidative stress and retrograde redox signaling. Pathogen- and herbivory-responsive pathways including jasmonic acid and salicylic acid were also up-regulated in juvenile primordia and indeed, exogenous application of jasmonic acid both delayed the appearance of adult traits and the decline of miR156 levels in maize seedlings. The successful amelioration of stress signals thus plays an important role in inducing vegetative phase change in maize. 12 untreated samples (8mm primordia of leaves 1-12) and 1 treated sample (leaf 5 primordium, 15mM JA treatment). 2 or more technical replicates per sample
2015-10-24 | E-GEOD-74295 | biostudies-arrayexpress
Project description:Hydrogen peroxide (H2O2) signals regulate plant growth and defense by orchestrating genome-wide transcriptional re-programming, however, the specific mechanisms that regulate H2O2-dependent gene expression are poorly understood. Here we report the identification of the Mediator complex subunit MED8 as regulator of H2O2 responses, through a genetic screen of EAL4 promoter. Interestingly, the introduction of med8 mutation in the catalase-deficient background was associated with enhanced activation of salicylic acid biosynthesis and signaling pathways. Surprisingly, however, med8 seedlings were more tolerant to oxidative stress generated by methyl viologen. This tolerance phenotype is associated with the hyperactivation of defense and hormone signaling pathways in particular salicylic acid and jasmonic acid-related pathways. In addition, analysis of MED8 interactomes revealed interaction with novel pathways expanding Mediator complex function to processes beyond transcription, including miRNA biogenesis and and mRNA processing. We establish MED8 as a new component within the regulation of oxidative stress responses and demonstrate that MED8 act as negative regulator of H2O2 -driven activation of defense gene expression.
2021-09-17 | PXD016615 | Pride
Project description:Leaf-to-leaf, systemic immune signaling known as systemic acquired resistance (SAR) is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to SAR in Arabidopsis thaliana, systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid (SA). Instead, we documented a moderate local but not systemic induction of abscisic acid (ABA) after infection of leaves with Psj. In contrast to SA or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or ABA triggered systemic immunity to Xtc. RNA-seq analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest and quantitative RT-PCR associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors possibly facilitating transcriptional reprogramming to potentiate immunity.
2014-11-24 | E-MTAB-3056 | biostudies-arrayexpress
Project description:Leaf-to-leaf, systemic immune signaling known as systemic acquired resistance (SAR) is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to SAR in Arabidopsis thaliana, systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid (SA). Instead, we documented a moderate local but not systemic induction of abscisic acid (ABA) after infection of leaves with Psj. In contrast to SA or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or ABA triggered systemic immunity to Xtc. RNA-seq analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest and quantitative RT-PCR associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors possibly facilitating transcriptional reprogramming to potentiate immunity.
2014-11-24 | E-MTAB-3063 | biostudies-arrayexpress
Project description:Enhancing grain production of rice (Oryza sativa L.) is a top priority in ensuring food security for human being. One approach to increase yield is to delay leaf senescence and to extend the available time for photosynthesis. microRNAs (miRNAs) are key regulators for aging and cellular senescence in eukayotes. However, miRNAs and their roles in rice leaf senescence remain unexplored. Here, we report identification of miRNAs and their putative target genes by deep sequencing of six small RNA libraries, six RNA-seq libraries and two degradome libraries from the leaves of two super hybrid rice, Nei-2-You 6 (N2Y6, age-resistant rice) and Liang-You-Pei 9 (LYP9, age-sensitive rice). Totally 372 known miRNAs and 162 miRNA candidates were identified, and 1145 targets were identified. Compared with the expression of miRNAs in the leaves of LYP9, the numbers of miRNAs up-regulated and down-regulated in the leaves of N2Y6 were 47 and 30 at early stage of grain-filling, 21 and 17 at the middle stage, and 11 and 37 at the late stage, respectively. Six miRNA families, osa-miR159, osa-miR160 osa-miR164, osa-miR167, osa-miR172 and osa-miR1848, targeting the genes encoding APETALA2 (AP2), zinc finger proteins, salicylic acid-induced protein 19 (SIP19), Auxin response factors (ARF) and NAC transcription factors, respectively, were found to be involved in leaf senescence through phytohormone signaling pathways. These results provided valuable information for understanding the miRNA-mediated leaf senescence of rice, and offered an important foundation for rice breeding. [miRNA] sample 1:The flag leaves at early stage of grain-filling of N2Y6 rice; sample 2: The flag leaves at middle stage of grain-filling of N2Y6 rice;sample 3:The flag leaves at late stage of grain-filling of N2Y6 rice; sample 4:The flag leaves at early stage of grain-filling of LYP9 rice; sample 5: The flag leaves at middle stage of grain-filling of LYP9 rice;sample 6:The flag leaves at late stage of grain-filling of LYP9 rice. [DGE]: samples 7-12 [degradome (targets)]: samples 13:The flag leaves at mixed stages of grain-filling of N2Y6 rice; sample 14:The flag leaves at mixed stages of grain-filling of LYP9 rice
2015-01-01 | E-GEOD-62200 | biostudies-arrayexpress