Functions of Arabidopsis SAUR proteins

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

Jason W. Reed (PI), Punita Nagpal (co-PI). Proposal number IOS-0920418: Functions of Arabidopsis SAUR proteins. Intellectual merit of the proposed activity The plant hormone auxin regulates plant growth and development by largely unknown mechanisms that include induction of gene expression and regulating cell polarity. The largest class of auxin-inducible genes are a family of SAUR (Small Auxin Up-Regulated) genes of unknown function. SAUR genes are present in all flowering plants and also in moss, and therefore may carry out a function conserved in all plants. This proposal is to determine functions of a subfamily of SAUR genes and the corresponding proteins in the model plant Arabidopsis thaliana. Preliminary results indicate that these SAUR genes regulate elongation of rapidly growing tissues, possibly by affecting auxin transport or some other cell biological function. Genetic and physiological approaches will be used to determine the developmental functions of the selected SAUR genes, their expression patterns, and whether they indeed affect auxin transport. Microscopy experiments will reveal the intracellular localization of SAUR proteins, and whether this is regulated by endogenous or environmental signals. These experiments will establish when and where these SAUR proteins are present, their effects on auxin tranport, and how they may control growth of plant tissues. Broader impact of the proposed activity Understanding how growth is controlled is a necessary prelude to developing a systems-level understanding of plant development incorporating inputs from multiple different hormonal and environmental signals. Knowledge from these experiments may ultimately enable practical approaches to manipulate growth patterns in crop plants. Since SAUR genes are present even in bryophytes, the study will be relevant to development of all plants. In the course of this research one post-doc and one graduate student as well as multiple undergraduates will be trained in research approaches and specific techniques.