Salinity induced gene expression profiling in 8 diverse rice genotypes

Whole genome transcriptional responses is profiled in the 0 & 120 mM NaCl stressed whole seedlings of four indica (Pokkali, PSBRc50, IR 58, BRRI dhan 29), two Japonica (Banikat, Nipponbare) and two wild (O. latifolia, O. Rufipogon) accessions of rice (that showed varied level of tolerance to salt stresses) to identify the salinity induced transcripts. Stress was imposed on 14 day old seedlings and total RNA from the whole seedlings was collected after 48 h of stressed period (i.e., from 16 day old seedlings). These data sets were used for two different analyses. Firstly, the gene expression responses of eight rice genotypes was interrogated by the weighted continuous morpho-physiological trait responses (on a scale of 0 to 1) using a modified version of the ‘Significance Analysis of Microarrays’ (SAM) to identify the genes whose expression changes significantly and which is relative to the changes in morpho-physiological traits over these rice genotypes. Secondly, the differentially expressed significant salinity induced genes were also identified in the tolerant and in the susceptible genotypes using Gene-spring software. The genes that enriched the important biological processes and molecular functions (as identified by Gene Ontology: Singular enrichment analysis) are discussed in a way to explain the roles of these genes in overall stress adaptation mechanism. Fourteen day old whole seedlings of 8 rice genotypes were treated with 0 & 120 mM NaCl stress for 48 hours each with three replications and the gene expressions were measured using Agilent Rice Gene Expression 4x44K Microarray.