Understanding how TAN1 and AIR9 mediate division plane positioning in Arabidopsis

University Of California-Riverside, Riverside CA

Investigators

Abstract

This research seeks to understand the mechanisms that regulate plant cell division positioning, which is required for plant growth and development. Critically, plants are essential for life, as they feed people and form the majority of biomass on the planet. Despite their critical roles, how plants position division planes is still mostly unknown. This project will investigate how functionally redundant proteins control division plane orientation in the dicot Arabidopsis thaliana by determining whether two unrelated division site-localized proteins interact with each other and how yet unknown proteins mediate the localization of these division site proteins and contribute to division plane positioning. The Broader Impacts include the intrinsic merit of the project as the results are likely to be generalizable to all flowering plants, including those of agronomic importance. Additional activities will involve the training of graduate and undergraduate students, and a postdoctoral researcher who will gain valuable soft and hard skills including experimental design, communication with other scientists, project management, and a deeper understanding of scientific ethics. Outreach activities are planned for elementary school students. Two unrelated microtubule binding proteins, TANGLED1 (TAN1) and AUXIN INDUCED IN ROOT CULTURES9 (AIR9), are together essential for division plane positioning. The current hypothesis is that TAN1 and AIR9 mediate division plane positioning by forming two distinct but equivalent hubs that localize independently to the Arabidopsis division site. To test this hypothesis, the investigator will assess whether these proteins interact with each other using a variety of biochemical and in vivo assays. In addition to assessing potential physical interactions, genetic interactions have also been tested by identifying enhancer mutants that alter division plane positioning in combination with air9 mutants. Several air9 enhancer mutants will be characterized via quantitative analysis of the mutant phenotype, localization of the affected protein and identification of protein interactions that mediate division plane positioning. Finally, structure and function analysis will be used to characterize domains of the division-site localized protein AIR9 that are essential for division plane positioning in plant cells as well as the protein(s) that recruit AIR9 to the division site. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.