Construction of a cDNA library of Lathyrus sativus inoculated with Mycosphaerella pinodes and the expression of potential defence-related expressed sequence tags (ESTs)

This study aimed to initiate the development of an EST database for Lathyrus sativus in order to identify L. sativus gene sequences similar to other plant genes functionally associated with disease response. A non-directional cDNA library was constructed from leaf and stem tissue collected from a resistant L. sativus plant (ATC 80878), 48 and 72 h post inoculation with Mycosphaerella pinodes. Eight hundred and eighteen L. sativus ESTs were generated. Fifty-three percent of the ESTs exhibited similarity to known sequences in public databases, and included genes encoding proteins and enzymes putatively involved in photosynthesis, metabolism, stress/ripening and signalling/communication. At least 50 ESTs, representing 29 unique gene sequences, were significantly similar to known plant genes potentially implicated in plant disease responses. These included genes associated with pathogen recognition, signalling transduction and transcription regulation, the phenylpropanoid pathway, hypersensitivity, PR proteins and disease resistance response proteins. Hierarchical cluster analysis of cDNA array expression data of these ESTs identified 16 defence-related ESTs potentially important in conferring stem resistance in the resistant L. sativus accession ATC 80878.