Comparative analysis of rice leaves transcriptome under control and drought stress conditions using EST data

Rice is the staple food for more than half the world's population, especially in developing countries. Drought is the most yield-limiting factor for rice production in Asia. The current study was conducted to identify the drought stress responsive genes through EST data analysis of two rice leaves libraries. EST libraries data under normal and drought stress conditions were downloaded from NCBI databank. Preprocessing, clustering and assembly of the EST sequences were done using EGassembler software. Generated contig and singleton sequences were used as template for BLASTx analysis against rice protein database and functional category assignment using CLC Protein Workbench software and AgriGO. The identified proteins in the normal and drought libraries were allocated to 70 and 82 functional categories, respectively. IDEG6 were used to identify significant differences between functional categories in control and drought stress libraries. Gene ontology analysis, revealed significant differences in 20 groups of molecular function, 35 groups of biological processes and 12 groups of the intracellular components. In order to find the significant differential expression between the two libraries, 4012 ESTs with unigene accession numbers were implemented through applying an algorithm by MATLAB software and were analyzed by IDEG6 software, where 42 genes were found to be differentially expressed between drought and normal conditions (31 up-regulated and 11 down-regulated genes). The up-regulated genes were involved in environmental and oxidative stress response, homestasis, proteolysis and glycolysis, while photosynthesis related genes were down-regulated.