The long term goal of this work is to understand how the hormonal and developmental signals which control the process of seed maturation in plants are integrated into the larger program of plant embryogenesis. This investigator proposes to continue his analysis of a key regulatory gene in this pathway identified by the vp1 mutant of maize and its apparent homolog, ABI3, in Arabidopsis. The functional complexity of VP1 suggests that interactions with other protein factors play a central role in its function. The P.I. will use both biochemical and genetic approaches that will identify and allow him to clone genes which may interact with VP1 and ABI3. Though VP1 and ABI3 share significant homology, the proteins are highly divergent in regions known to be functionally important in VP1. The P.I. will also determine the extent to which VP1 and ABI3 sequences are functionally interchangeable in maize cells and in transgenic Arabidopsis. This will also provide a functional map of ABI3, comparable to that in hand for VP1; it will also aid in bringing the genetics available in Arabidopsis to bear on the maturation pathway and ABI3 function. The P.I. also plans to analyze new mutants in the maturation pathway identified in both maize and Arabidopsis. He is specifically interested in identifying new mutations that affect VP1 or ABI3 expression or function.
