Plant & Animal Genomes XVI Conference Plant & Animal Genomes XVI ConferenceJanuary 12-16, 2008
Town & Country Convention Center
San Diego, CA
Santy Peraza-Echeverria , Andrew C. James , Blondy Canto-Canché , Eduardo Castillo-Castro
Commercial banana cultivars are highly susceptible to a wide spectrum of pathogens. The use of genetic transformation is an attractive approach to develop pathogen resistance in banana by transferring resistance (R) genes into susceptible cultivars. So far, eight classes of R genes have been cloned and characterized from other crops. The Pto gene from tomato encodes a serine/threonine protein kinase (STK) and represents one of these classes of R genes. Overexpression of Pto in tomato can lead to both bacterial and fungal resistance. These findings make this type of gene an interesting candidate for engineering broad-spectrum pathogen resistance. In the present study, a pair of degenerate primers based on conserved subdomains of plant STKs similar to the tomato Pto protein were used to amplify similar sequences in banana. A fragment of ~550 bp was amplified, cloned and sequenced. The sequence analysis of several clones revealed 13 distinct sequences highly similar to STKs. Based on their significant similarity with the tomato Pto protein, seven of them were classified as Pto resistance gene candidates (Pto-RGCs). Multiple sequence alignment of the banana Pto-RGC products revealed that these sequences contain several conserved subdomains present in most STKs and also several conserved residues that are crucial for Pto function. Moreover, the phylogenetic analysis showed that the banana Pto-RGCs were clustered with Pto suggesting a common evolutionary origin with this R gene. The Pto-RGCs isolated in this study represent a valuable sequence resource that could assist in the development of disease resistance in banana.