B2 and B3 Raf-like protein kinases activate SnRK2s and are essential for abscisic acid signaling
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE152691 | GEO | 2021/03/24
REPOSITORIES: GEO
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Project description:B2 and B3 Raf-like protein kinases activate SnRK2s and are essential for abscisic acid signaling
| PRJNA640131 | ENA
Project description:Phytohormone abscisic acid (ABA) plays a key role in stomata closure, osmostress acclimation, and vegetative and embryonic dormancy. Group B3 Raf protein kinases (B3-Rafs) serve as positive regulators of ABA and osmostress signaling in the moss Physcomitrium patens and the angiosperm Arabidopsis thaliana. While P. patens has a single B3-Raf called ARK, specific members of B3-Rafs among six paralogs regulate ABA and osmostress signaling in A. thaliana, indicating functional diversification of B3-Rafs in angiosperms. However, we found that the liverwort Marchantia polymorpha, belonging to another class of bryophytes, has three paralogs of B3-Rafs, MpARK1, MpARK2, and MpARK3, with structural variations in the regulatory domains of the polypeptides. By reporter assays of the P. patens ark line and analysis of genome-editing lines of M. polymorpha, we found that these B3-Rafs are functionally redundant in ABA response, with respect to inhibition of growth, tolerance to desiccation and expression of stress-associated transcripts, the majority of which are under the control of the PYR/PYL/RCAR-like receptor MpPYL1. Interestingly, gemmae in gemma cups were germinating only in mutant lines associated with MpARK1, indicating that dormancy in the gametophyte is controlled by a specific B3-Raf paralog. These results indicated not only conservation of the role of B3-Rafs in ABA and osmostress response in liverworts but also functional diversification of B3-Rafs, which is likely to have occurred in the early stages of land plant evolution.
| S-EPMC9370073 | biostudies-literature
Project description:The Arabidopsis hypocotyl is an excellent model for understanding radial growth in plants. Division of the cambial cells and their subsequent differentiation into xylem and phloem drives radial expansion of the hypocotyl. Following the transition to reproductive growth, a phase change occurs in the Arabidopsis hypocotyl. During this second phase, the relative rate of xylem production is dramatically increased compared to that of phloem and xylem fibres containing thick secondary cell walls also form, which results in the production of xylem tissue comparable to the wood of trees. Abscisic acid (ABA) is a phytohormone known to have a major role in various plant processes, including in the response to changes in environmental conditions and in the promotion of seed dormancy. Using two different genetic backgrounds and different environmental conditions, we identified a set of core of transcriptional changes associated with the switch to the second phase of growth in the hypocotyl. ABA signalling pathways were identified as being as significantly over-represented in this set of core genes. Reverse genetic analysis demonstrated that mutants defective in ABA-biosynthesis enzymes exhibited significantly delayed fibre production without affecting the xylem:phloem ratio. The altered morphology is also reflected at the transcript level, with a reduced expression of marker genes associated with fibre formation in aba1 mutants. The application of exogenous ABA to the mutant rescued the phenotype, restoring fibre differentiation to wild-type levels. Taken together the data reveals an essential role for ABA in the regulation of fibre formation.
2018-05-23 | GSE114782 | GEO
Project description:The Arabidopsis hypocotyl is an excellent model for understanding radial growth in plants. Division of the cambial cells and their subsequent differentiation into xylem and phloem drives radial expansion of the hypocotyl. Following the transition to reproductive growth, a phase change occurs in the Arabidopsis hypocotyl. During this second phase, the relative rate of xylem production is dramatically increased compared to that of phloem and xylem fibres containing thick secondary cell walls also form, which results in the production of xylem tissue comparable to the wood of trees. Abscisic acid (ABA) is a phytohormone known to have a major role in various plant processes, including in the response to changes in environmental conditions and in the promotion of seed dormancy. Using two different genetic backgrounds and different environmental conditions, we identified a set of core of transcriptional changes associated with the switch to the second phase of growth in the hypocotyl. ABA signalling pathways were identified as being as significantly over-represented in this set of core genes. Reverse genetic analysis demonstrated that mutants defective in ABA-biosynthesis enzymes exhibited significantly delayed fibre production without affecting the xylem:phloem ratio. The altered morphology is also reflected at the transcript level, with a reduced expression of marker genes associated with fibre formation in aba1 mutants. The application of exogenous ABA to the mutant rescued the phenotype, restoring fibre differentiation to wild-type levels. Taken together the data reveals an essential role for ABA in the regulation of fibre formation. We used microarrays to probe transcripome changes I Arabidopsis hypocotyls following transition from phase I to phase II
2018-05-19 | GSE114638 | GEO
Project description:Background: Abscisic acid (ABA) regulates various developmental processes and stress responses over both short (i.e. hours or days) and longer (i.e. months or seasons) time frames. To elucidate the transcriptional regulation of early responses of grapevine (Vitis vinifera) responding to ABA, different organs of grape (berries, shoot tips, leaves, roots and cell cultures) were treated with 10 μM (S)-(+)-ABA for 2 h. NimbleGen whole genome microarrays of Vitis vinifera were used to determine the effects of ABA on organ-specific mRNA expression patterns. Results: Transcriptomic analysis revealed 839 genes whose transcript abundances varied significantly in a specific organ in response to ABA treatment. No single gene exhibited the same changes in transcript abundance across all organs in response to ABA. The biochemical pathways affected by ABA were identified using the Cytoscape program with the BiNGO plug-in software. The results indicated that these 839 genes were involved in several biological processes such as flavonoid metabolism, response to reactive oxygen species, response to light, and response to temperature stimulus. ABA affected ion and water transporters, particularly in the root. The protein amino acid phosphorylation process was significantly overrepresented in shoot tips and roots treated with ABA. ABA affected mRNA abundance of genes (CYP707As, UGTs, and PP2Cs) associated with ABA degradation, conjugation, and the ABA signaling pathway. ABA also significantly affected the expression of several transcription factors (e.g. AP2/ERF, MYC/MYB, and bZIP/AREB). The greatest number of significantly differentially expressed genes was observed in the roots followed by cell cultures, leaves, berries, and shoot tips, respectively. Each organ had a unique set of gene responses to ABA. Conclusions: This study examined the short-term effects of ABA on different organs of grapevine. The responses of each organ were unique indicating that ABA signaling varies with the organ. Understanding the ABA responses in an organ-specific manner is crucial to fully understand hormone action and plant responses to water deficit.
2016-03-01 | GSE78798 | GEO
Project description:Abscisic acid (ABA) plays essential roles in plant development and responses to environmental stress. ABA induces subcellular translocation and degradation of the guanine nucleotide exchange factor RopGEF1 thus facilitating ABA core signal transduction. However, the underlying mechanisms for ABA-triggered RopGEF1 trafficking/degradation remain unknown. Studies have revealed that RopGEFs associate with receptor-like kinases to convey developmental signals to small ROP GTPases. However, how the activities of RopGEFs are modulated is not well understood. Type 2C protein phosphatases stabilize the RopGEF1 protein, indicating that phosphorylation may trigger RopGEF1 trafficking and degradation. We have screened inhibitors followed by several protein kinase mutants and find that quadruple mutant plants in the Arabidopsis calcium-dependent protein kinases (CPKs) cpk3/4/6/11 disrupt ABA-induced trafficking and degradation of RopGEF1. Moreover, cpk3/4/6/11 partially impairs ABA inhibition of germination. Several CPKs interact with RopGEF1. CPK4 binds to and phosphorylates RopGEF1 and promotes the degradation of RopGEF1. CPK-mediated phosphorylation of RopGEF1 at specific N-terminal serine residues causes the degradation of RopGEF1 and mutation of these sites also compromises the RopGEF1 over-expression phenotype in root hair development in Arabidopsis. Our findings establish the physiological and molecular functions and relevance of calcium-dependent protein kinases in regulation of RopGEF1 and illuminate physiological roles of a CPK-GEF-ROP module in abscisic acid signaling and plant development. We further discuss that CPK-dependent RopGEF degradation during abiotic stress could provide a mechanism for down-regulation of RopGEF-dependent growth responses.
2019-11-12 | PXD009421 | Pride
Project description:Abscisic acid (ABA) plays essential roles in plant development and responses to environmental stress. ABA induces subcellular translocation and degradation of the guanine nucleotide exchange factor RopGEF1 thus facilitating ABA core signal transduction. However, the underlying mechanisms for ABA-triggered RopGEF1 trafficking/degradation remain unknown. Studies have revealed that RopGEFs associate with receptor-like kinases to convey developmental signals to small ROP GTPases. However, how the activities of RopGEFs are modulated is not well understood. Type 2C protein phosphatases stabilize the RopGEF1 protein, indicating that phosphorylation may trigger RopGEF1 trafficking and degradation. We have screened inhibitors followed by several protein kinase mutants and find that quadruple mutant plants in the Arabidopsis calcium-dependent protein kinases (CPKs) cpk3/4/6/11 disrupt ABA-induced trafficking and degradation of RopGEF1. Moreover, cpk3/4/6/11 partially impairs ABA inhibition of germination. Several CPKs interact with RopGEF1. CPK4 binds to and phosphorylates RopGEF1 and promotes the degradation of RopGEF1. CPK-mediated phosphorylation of RopGEF1 at specific N-terminal serine residues causes the degradation of RopGEF1 and mutation of these sites also compromises the RopGEF1 over-expression phenotype in root hair development in Arabidopsis. Our findings establish the physiological and molecular functions and relevance of calcium-dependent protein kinases in regulation of RopGEF1 and illuminate physiological roles of a CPK-GEF-ROP module in abscisic acid signaling and plant development. We further discuss that CPK-dependent RopGEF degradation during abiotic stress could provide a mechanism for down-regulation of RopGEF-dependent growth responses.
2019-11-12 | PXD009422 | Pride
Project description:Abscisic acid (ABA) is an essential hormone that allows plants to respond to environmental stresses such as high salinity, drought and cold. It also plays a pivotal role in seed maturation and germination. Because of its importance, transcriptome changes in response to ABA have been profiled extensively by the plant community. Very few ChIP-chip/seq of ABA-related TFs have been reported to date. To fill the knowledge gap about how ABA works at the transcriptional level, we carried out ChIP-seq on 21 TFs from 11 different families using both mock- and ABA-treated conditions. Analyses of the resulting 122 ChIP-seq datasets identified 326,698 TF binding events using a stringent statistical cutoff. Based on our data, a comprehensive regulatory network in Arabidopsis thaliana was constructed. We uncovered determinants of dynamic TF binding and defined a hierarchy among TFs to explain differential gene expression and pathway feedback regulation. By extrapolating regulatory characteristics observed for the canonical ABA pathway components, we identified a new family of transcriptional regulators modulating ABA and salt responsiveness, and demonstrate their utility to modulate plant resilience to osmotic stress.
2017-02-03 | GSE80564 | GEO
Project description:Abscisic acid (ABA) is an essential hormone that allows plants to respond to environmental stresses such as high salinity, drought and cold. It also plays a pivotal role in seed maturation and germination. Because of its importance, transcriptome changes in response to ABA have been profiled extensively by the plant community. Very few ChIP-chip/seq of ABA-related TFs have been reported to date. To fill the knowledge gap about how ABA works at the transcriptional level, we carried out ChIP-seq on 21 TFs from 11 different families using both mock- and ABA-treated conditions. Analyses of the resulting 122 ChIP-seq datasets identified 326,698 TF binding events using a stringent statistical cutoff. Based on our data, a comprehensive regulatory network in Arabidopsis thaliana was constructed. We uncovered determinants of dynamic TF binding and defined a hierarchy among TFs to explain differential gene expression and pathway feedback regulation. By extrapolating regulatory characteristics observed for the canonical ABA pathway components, we identified a new family of transcriptional regulators modulating ABA and salt responsiveness, and demonstrate their utility to modulate plant resilience to osmotic stress.
2017-02-03 | GSE80565 | GEO
Project description:RAF inhibitor therapy yields significant reductions in tumour burden in the majority of V600E-positive melanoma patients; however, resistance occurs within 2-18 months. Here we demonstrate that the mixed lineage kinases (MLK1-4) are MEK kinases that reactivate the MEK/ERK pathway in the presence of RAF inhibitors. Expression of MLK1-4 mediates resistance to RAF inhibitors and promotes survival in V600E-positive melanoma cell lines. Furthermore, we observe upregulation of the MLKs in 9 of 21 melanoma patients with acquired drug resistance. Consistent with this observation, MLKs promote resistance to RAF inhibitors in mouse models and contribute to acquired resistance in a cell line model. Lastly, we observe that a majority of MLK1 mutations identified in patients are gain-of-function mutations. In summary, our data demonstrate a role for MLKs as direct activators of the MEK/ERK pathway with implications for melanomagenesis and resistance to RAF inhibitors.
| S-EPMC4046110 | biostudies-literature