Modulation of ABA signaling by Ca2+-dependent posttranslational regulation
Final Report Abstract
Aims of the DFG Project "Modulation of ABA signaling by Ca 2+-dependent posttranslational regulation” were to test the activation of SnRK2 kinases in ABA signaling by calcium dependent processes and to study the interaction of ABA-signaling with biotic signaling pathways. We could further corroborate the initial finding that CBL1 and CIPK1 are required for stomatal aperture regulation. We could furthermore show that SnRK2 kinases are not directly regulated by CIPK1 via phosphorylation but probably via an indirect mechanism. We identified downstream processes regulated by the activity of SnRK2 kinases, including the subnuclear localization of WRKY40 to PHYTOCHOME B-containing nuclear bodies. Upon ABA- treatment, WRKY40 protein relocalizes to the nucleoplasm within 15 minutes, which might pose a new posttranslational regulatory mechanism for WRKY transcription factors. Localization to PHYB- containing nuclear bodies might link ABA to light-signaling in seed germination. Following up on the role of WRKY transcription factors in ABA signaling, we pursued a reverse genetic screen and identified WRKY43 as a negative regulator of ABA-inhibition of seed germinate. In further genetic analyses we could show that WRKY43 regulates components of the central AFL-network in seed germination and influences lipid fatty acid composition which results in an increased abiotic stress tolerance of wrky43 seeds. Overall this project could show that calcium dependent processes have a pivotal role in ABA-signal transduction and that biotic signaling pathways and ABA-signaling are intricately linked not only in stomatal aperture regulation but also during seed germination.
Publications
- (2012). Screening for in planta protein-protein interactions combining bimolecular fluorescence complementation with flow cytometry. Plant Methods 8, 25
Berendzen, K.W., Böhmer, M., Wallmeroth, N., Peter, S., Vesic, M., Zhou, Y., Tiesler, F.K., Schleifenbaum, F., and Harter, K.
(See online at https://doi.org/10.1186/1746-4811-8-25) - (2013). Guarding the green: pathways to stomatal immunity. Mol Plant Microbe Interact 26, 626-632
Sawinski, K., Mersmann, S., Robatzek, S., and Böhmer, M.
(See online at https://doi.org/10.1094/MPMI-12-12-0288-CR) - (2015). "Investigation of plant abiotic stress tolerance by proteomics and phosphoproteomics," in Elucidation of Stress Signaling in Plants: A Functional Genomic Perspective, ed. G.K. Pandey. Springer), 926
Böhmer, M.
- (2015). Distinct Cellular Locations of Carbonic Anhydrases Mediate Carbon Dioxide Control of Stomatal Movements. Plant Physiol 169
Hu, H., Rappel, W.J., Occhipinti, R., Ries, A., Böhmer, M., You, L., Xiao, C., Engineer, C.B., Boron, W.F., and Schroeder, J.I.
(See online at https://doi.org/10.1104/pp.15.00646) - (2015). Dynamic subnuclear relocalisation of WRKY40 in response to Abscisic acid in Arabidopsis thaliana. Sci Rep 5, 13369
Geilen, K., and Böhmer, M.
(See online at https://doi.org/10.1038/srep13369) - (2015). Dynamic subnuclear relocalization of WRKY40, a potential new mechanism of ABA-dependent transcription factor regulation. Plant Signal Behav 10, e1106659
Geilen, K., and Böhmer, M.
(See online at https://doi.org/10.1080/15592324.2015.1106659) - WRKY43 regulates polyunsaturated fatty acid content and seed germination under unfavourable growth conditions. Scientific Reports volume 7, Article number: 14235 (2017)
Geilen, K., Heilmann, M., Hilmer, S. and Böhmer, M.
(See online at https://doi.org/10.1038/s41598-017-14695-0)
