Subcellular control of endogenous auxin phenylacetic acid in plants

• Applicant: Kristýna Bieleszová, Ph.D.
• Subject Area: Plant Physiology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 555156061

The phytohormone auxin is a major regulator of plant development. The cellular abundance of auxin is controlled by an interplay of biosynthesis, molecular inactivation, as well as, intra- and intercellular transport. As the most prevalent auxin indole-3-acetic acid (IAA) has been extensively studied in plants, whereas the potentially deviating functions of other endogenous auxins, including phenylacetic acid (PAA), are largely unknown. Our goal is to elucidate a subcellular function of PAA, using newly developed PAA derivatives. We will study the PAA intersection with PILS proteins, which are facilitators of intracellular compartmentalisation of auxin. PILS are structurally similar to the well-characterised PIN auxin efflux carriers, but their substrate binding site is predicted to be smaller. We hypothesize that PAA, as a smaller auxin, may exhibit preferred binding to PILS proteins. We will explore the PILS-dependent effects of PAA and will map the subcellular PAA levels, which will allow us to dissect the subcellular competition of auxins and link it to PILS-dependent growth control.

• DFG Programme: WBP Position