Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Poster: Gene Isolation
            

GENOME TRANSCRIPT ANALYSIS OF ROOT NODULES IN MEDICAGO TRUNCATULA REVEALS A NOVEL GROUP OF CALCIUM BINDING PROTEINS

¹ Department of Agronomy and Plant Genetics, University of Minnesota, 411 Borlaug Hall, Upper Buford Circle, St. Paul, MN 55108

² Department of Plant Biology, University of Minnesota

³ USDA-ARS, Plant Science Research Unit

To gain deeper insight in the correlation between the global gene expression patterns and nodule function, we performed transcript profiling of nodules in Medicago truncatula. Assembly of ESTs led to the discovery of six TCs which code for calcium-binding proteins with sequence similarity to calmodulins. Unlike constitutive calmodulins with four EF-hands, these calmodulin-like proteins contain two to three EF-hands. RNA blot analysis indicated that the accumulation of messenger is highly nodule-specific. Furthermore, to identify the presence of messenger RNA in different cell types of nodules, in situ hybridization was carried out and preliminary results showed a preferential accumulation of messenger RNA in infected cells in contrast to non-infected cells. One of the calcium-binding proteins was expressed in E. coli and the purified fusion protein was used for raising antibody as well as for calcium-binding assay. Genomic clones for the novel nodule specific calmodulin-like proteins have been isolated and will be used for dissecting the genomic structure and cis-acting elements in the promoters of gene family members.