Plant & Animal Genomes XI Conference

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

Poster: Genome Sequencing & ESTs
            

DIFFERENTIAL EXPRESSION OF DEFENSE-RELATED GENES IDENTIFIED FROM SWEET ORANGE TISSUES THROUGH EST ANALYSIS

¹ Citriculture Center Sylvio Moreira / Agronomic Institute - Millenium Institute - CNPq/MCT, Cordeirópolis, SP, Brazil

² Embrapa / Agronomic Institute, Cordeirópolis, SP, Brazil

Several plant defense-related genes have been identified and cloned from different plant species through PCR-based assays and degenerate primers. However, the question of whether these putative genes are expressed still remains unanswered. Expressed sequence tags (EST's) represent a more effective alternative to identify large number of genes that are actually expressed under specific conditions. So far, we have generated more than 40,000 EST's from leaves and fruits of sweet orange plants grown under different conditions and at different growth stages. As a result, a large number of non-redundant clusters have been found to encode proteins with high level of homology to known defense-related proteins. Among them, the most commonly found products are pathogenesis-related proteins, enzymes involved in the synthesis of phytoalexins, proline- and hydroxiproline- rich proteins, antioxidant enzymes, WRKY-like transcription factors, 14-3-3 proteins, defense response modulators, resistance gene homologs, and proteins involved in cell death. An in silico differential display analysis of these genes is presented.