Poster: Membrane transport

Abs # 185: Analysis of transporters involved in import of amino acids into developing legume seeds

Presenter:	Grennan, Aleel K, aleel@mail.wsu.edu
Authors	Grennan, Aleel K (A)   Beneski, Erin  (A)   Doris, Rentsch  (B)   Mechthild, Tegeder  (C) (D)
Affiliations:	(A): School of Biological Sciences, Washington State University (B): Institute of Plant Sciences, University of Bern, Switzerland (C): Center for Reproductive Biology, Washington State University (D): Institute of Biotechnology, Washington State University

Legumes, with their storage protein rich seeds, are agronomically important crops worldwide that are utilized both as animal feed and for human nutrition. For synthesis of the storage protein, large amounts of amino acids have to be transported from photosynthetically active source leaves to seed sinks. We are interested in understanding the mechanisms of amino acid transport to cotyledons of temperate (Pisum sativum) and tropical (Phaseolus vulgaris) legumes for development and storage protein accumulation. To identify transporters involved in transport of amino acids to seeds, cDNA libraries were constructed from pea and bean cotyledons. Functional screening of the libraries in different yeast mutants and under varying selective conditions led to the isolation of several new legume AAPs. These transporters were functionally analyzed in yeast and their organ-specific expression in pea and bean plants was resolved. The AAPs were shown to have individual expression patterns suggesting distinct roles within the plant. Studies on regulation of transporter expression demonstrated that the AAPs are developmentally regulated. AAP expression also depends on the nitrogen source supplied and is regulated by diurnal rhythm. This work was supported by the National Research Initiative Competitive Grants Program-U.S. Department of Agriculture grant no. 2001–35318–10990