Accumulation of Defence Response-related and Unique Expressed Sequence Tags during the Incompatible Interaction in the Oryza sativa-Magnaporthe oryzae Pathosystem

Resistance gene-dependent accumulation of expressed sequence tags (ESTs) was studied in a blast resistant, Oryza sativa ssp. indica cv. Tetep after challenge inoculation with an incompatible race of Magnaporthe oryzae. The nucleotide sequence of 287 randomly selected cDNA clones from the rice cDNA library constructed from the RNA isolated after challenge inoculation of the host was obtained and submitted in NCBI Genbank (Accession Nos. DN475717-DN475431). Of these, 184 (63%) ESTs were highly representative of the rice transcriptomes. A set of 178 unique transcripts was identified after assembly of 287 ESTs into unigenes. These unigenes were categorized into 17 functional groups. Analysis of this EST library illustrated a broad functional representation. Twenty-one unigenes were identified as putative homologues of the genes that were up regulated during host-pathogen interaction. Similarity search of 178 unigenes with NCBI database of 14 plants unigenes showed similarity ranging from 29-100%. The unigenes obtained in this study were physically located on the pseudomolecules of rice genome. This information can be used for determining the arrays of genes being expressed during Oryza sativa-M. oryzae interactions, which will be helpful in understanding the molecular basis of disease resistance.