Faculty Member Receives NSF ARRA Grant
Elsbeth Walker recently received a $400,000 two-year grant from NSF as part of the ARRA program.
The ultimate goal of this grant is a thorough understanding of the mechanisms by which plants acquire and then maintain the correct levels of iron and other transition metals in cells and tissues. Plants use a variety of complex mechanisms to acquire sparingly soluble iron from the soil, translocate iron within and between organs, and signal iron status of above ground parts back to the roots where primary iron acquisition is accomplished. In spite of rapid progress in understanding several of these processes in recent years, little is known about molecules involved in the processes that plants use to move metals on a large scale: from organ to organ, or across several tissues within an organ. This work on the Yellow Strip-Like (YSL) family of proteins is focused on exactly these large scale, whole plant processes: YSL transporters are required for normal iron, zinc, and copper movement in both vegetative and reproductive tissues.
She has hypothesized that YSLs function to pull metals from the xylem stream into the intercoastal portions of the leaf. Furthermore, regulated YSL expression acts as a cutoff valve that shuts down metal uptake into mature photosynthetic tissue to spare limiting metals for the shoot apical meristem and reproductive tissues during periods of metal insufficiency. The project proposed here will test this model. In order to improve our understanding of the roles that YSL proteins play, the lab will develop more reliable and straightforward assays that will allow them to define the transport activities of the YSL transporters. By knowing the relative affinities of each YSL for particular metal ligands, they can understand the specific biochemical roles of each YSL *in planta.* In the course of this project, they will also define the roles of additional YSL family members in metal ion movement during germination and during seed development.
