Transcriptome profiling of lentil in response to Ascochyta lentis infection

Aim of study: The purpose was to identify some general and genotypic-specific defense responses, in order to obtain a set of candidate genes presumably involved in the resistance. Area of study: The experiment was carried out in León, Spain. Material and methods: We have analyzed the response of three lentil genotypes to Ascochyta lentis (isolate AL 84) at transcriptomic level using the Massive Analysis of cDNA Ends (MACE) technique: the susceptible cultivar 'Lupa', the moderately resistant 'ILL5588' and the resistant wild accession 'BG 16880' (L. culinaris subsp. orientalis). Main results: MACE results yielded a total of 50,935 contigs. The average number of detected contigs in each of the six samples was approximately of 40,000. In response to Ascochyta infection, the jasmonic acid pathway and the lignin biosynthesis were up-regulated in resistant genotypes, while they were down-regulated in the susceptible one. The response to chitin, the salicylic pathway and the auxin response were activated only in the resistant L. c. culinaris genotype, while the giberellin synthesis was only induced in the susceptible L. c. culinaris cv. 'Lupa'. A set of 18 lentil gene sequences putatively involved in the response to the pathogen were validated by RT-qPCR. Research highlights: It can be concluded that in response to the infection by Ascochyta, the lignin biosynthesis and the JA pathway were critical for the resistance, while the giberellin synthesis seems to be related with susceptibility to the pathogen.