Project description
cGMP pathway triggers rapid auxin responses in plants
The plant hormone auxin, in contrast to slower transcription mediated mechanisms, induces rapid responses involving a non-transcriptional mechanism. One of these responses is rapid root growth inhibition. However, the biochemical pathways and processes responsible are highly complex and remain unclear. With the support of the Marie Skłodowska-Curie Actions programme, the A-TARGET project will follow the lead of their previous studies, which suggest that the classical 'second messenger' cyclic GMP (cGMP) plays an important role by triggering calcium influx and cytosolic calcium oscillations. The project aims to test the hypothesis that cGMP, activated in an auxin-dependent way, acts as a second messenger that targets cyclic nucleotide-gated calcium channels to trigger rapid auxin responses in plants.
Objective
Rapid auxin responses initiate cellular changes, which are important for rapid, auxin-induced root growth inhibition and root gravitropism. Accumulating evidence shows that these rapid responses are mediated by TIR1/AFB signaling: Auxin enters the cell by influx or diffusion and activates the AFB1; within seconds, AFB1 activates a trio of tightly connected rapid responses, including PM depolarization, CNGC14-dependent cytosolic Ca2+ increase, and apoplast alkalinization, which lead to rapid root growth inhibition. However, how AFB1 mediates these rapid cellular responses via CNGC14 remains unknown.
Until recently, my host lab found that TIR1/AFBs have additional Guanylate cyclase activity and that its product, cGMP, rapidly and transiently increases in roots after auxin treatment. Importantly, application of cell-permeable cGMP triggers cytosolic Ca2+ increase in a CNGC14-dependent manner and rapid root growth inhibition in Arabidopsis. These observations collectively imply a linear AFB1 - cGMP - CNGC14 - Ca2+ non-transcriptional signaling pathway, which explains well at least part of the mysterious rapid auxin responses. However, how the auxin perception product, cGMP regulates CNGC14 and orchestrates Ca2+ influx is still unclear in planta. Thus, filling this major knowledge gap is eagerly awaited and will open entirely new possibilities for a mechanism of cytosolic Ca2+ oscillation in planta.
In this proposed research, I aim to test the hypothesis that AFB1-generated cGMP acts as a second messenger, targeting CNGC14 to trigger rapid auxin responses in plants. We will i) clarify the binding between cGMP and CNGC14 in vitro and in vivo; ii) test the importance of cGMP binding to CNGC14 functions in plants; iii) explore the mechanism, by which cGMP regulates CNGC14.
My investigation will not only be a significant step in our understanding of non-transcriptional auxin mechanisms but will have huge implications for other rapid, Ca2+-dependent cellular responses.
Keywords
Project’s keywords as indicated by the project coordinator. Not to be confused with the EuroSciVoc taxonomy (Fields of science)
Project’s keywords as indicated by the project coordinator. Not to be confused with the EuroSciVoc taxonomy (Fields of science)
Programme(s)
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
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HORIZON.1.2 - Marie Skłodowska-Curie Actions (MSCA)
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Topic(s)
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Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
Funding Scheme
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Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
HORIZON-TMA-MSCA-PF-EF - HORIZON TMA MSCA Postdoctoral Fellowships - European Fellowships
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Call for proposal
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(opens in new window) HORIZON-MSCA-2024-PF-01
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3400 KLOSTERNEUBURG
Austria
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