Identification of differentially expressed sequences in the non-compatible interaction Musa acuminata - Mycosphaerella fijiensis Morelet

Black leaf streak disease caused by Mycosphaerella fijiensis Morelet is considered the most destructive and costly foliar disease of bananas and plantain. An important step for the elucidation of molecular mechanisms of the disease resistance is to know about genes involved in plant defense response to pathogens. Identification of differentially expressed sequences in resistant genotype ‘Calcutta 4’ (Musa acuminata, AA) at an early stage of infection with M. fijiensis (6 to 12 days post inoculation) from a suppressed subtractive library (SSH) was carried out. A number of 63 ESTs, which include 42 singletons and 21 contigs were obtained by assembling 97 sequences with CAP3 algorithm. Identification of sequences according to their homology with sequences stated at protein non-redundant database GenBank, allowed to gather them in six functional categories: protein destiny (1.6%), oxidative stress (4.8%), metabolism (6.3%), energy production (6.3%), unknown function (38.1%) and without homology (42.8%). Results obtained will contribute to a better understanding of pathosystem, which allow the design of new strategies related to genetic improvement of banana. Keywords: Black leaf streak disease, expressed sequence tags, functional gene classification, Musa spp.,subtractive library