Plant & Animal Genome IX Conference

Poster: Large Insert Libraries, Gene Isolation, Etc.
P02_38.html

DEVELOPMENT OF A SET OF PHYLOGENETICALLY INFORMATIVE BAC LIBRARIES IN THE GENUS PHASEOLUS

Dept. of Agronomy and Range Science, University of California, 1 Shields Avenue, Davis, CA 95616-8515

The phylogeny of the genus Phaseolus, in general, and of P. vulgaris (common bean) in particular, is well understood. Thus, Phaseolus provides a model to study short-term (on an evolutionary time scale) changes at the level of the genome and the relationship between genomic and phenotypic changes. Specifically, we are seeking to understand the evolution of the arcelin/phytohemagglutinin/alpha-amylase-inhibitor (APA) locus. This locus represents a small, multigene family comprised within approximately 250 kb on linkage group B4. The family plays a role in plant defense against predators, principally insects. The original subfamily at the APA locus was the phytohemagglutinin family (PHA) present in most legumes, including most Phaseolus species such as P. lunatus (lima bean: PHA⁺/alphaAI^-/ARL^-). An additional subfamily, the alpha-amylase inhibitor subfamily (alphaAI), appeared later and is currently found only in the P. vulgaris complex (also containing P. polyanthus, P. coccineus, and P. acutifolius; PHA⁺/alphaAI⁺/ARL^-). Finally, the third subfamily, the arcelin subfamily appeared within the last 500,000 years in some wild, Mesoamerican accessions of P. vulgaris (PHA⁺/alphaAI⁺/ARL⁺). We will report on the development and characterization of several BAC libraries from selected genotypes that will allow us to gain insights in how the APA gene family has recently expanded and acquired novel resistance phenotypes.