Cellular modes of action of KIPK family kinases, new regulators of negative gravitropism and seedling soil penetration

• Applicant: Professor Dr. Claus Schwechheimer
• Subject Area: Plant Cell and Developmental Biology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 548863490

Understanding the mechanisms controlling plant growth in response to their environment is one of the most fascinating topics in plant biology. We have identified KIPK and KIPKL1 AGC1 family protein kinases as regulators of gravitropic hypocotyl bending. We have further shown that this process is important for successful soil penetration of germinating Arabidopsis thaliana seedlings where contact with soil particles require growth reorientation. We will study the functional interplay of KIPK and KIPKL in the regulation of proteins with a role in cytoskeleton regulation (ARK kinesins, NET1A actin-binding proteins) and intracellular trafficking (CHC, VPS41) to understand relevant downstream processes. Using biochemical, cell biological and genetic analyses, we will determine the regulatory role of KIPK and KIPKL in the (phospho)regulation of the said interactors. Using markers for the microtubule and actin cytoskeleton, we will determine the arrangement of microtubules and the actin cytoskeleton during gravitropic bending and analyse to what extent these processes are impaired in kipk kipkl1 mutants. These studies will not only further our understanding the processes relevant for hypocotyl gravitropism but they may also influence our understanding of other, related AGC1 family protein kinases, whose mode of action has, as-yet, only been explained through the regulation of auxin transport.

• DFG Programme: Research Grants