Comparative transcriptome analysis reveals molecular response to salinity stress of salt-tolerant and sensitive genotypes of indica rice at seedling stage

Abiotic stresses, such as salinity, greatly threaten the growth and productivity of plants. Rice (Oryza sativa L.) is one of the most important food crops, as well as a monocot model for genomic research. To obtain a global view of the molecular response to salinity stress, we conducted a leaf transcriptome analysis on rice seedlings. Two cultivars of rice subspecies indica, including the salt-tolerant genotype Xian156 and the salt-sensitive genotype IR28, were used in the present study. Eighteen RNA libraries were obtained from these two genotypes at three timepoints (0 h, 48 h and 72 h) after applying salinity stress. We obtained the reference-guided assembly of the rice transcriptome, which resulted in 1,375 novel genes, including 1,371 annotated genes. A comparative analysis between genotypes and time points showed 5,273 differentially expressed genes (DEGs), of which 286 DEGs were only found in the tolerant genotype. The Disease resistance response protein 206 and TIFY 10 A were differentially expressed, which were validated by quantitative real-time PCR. The differentially expressed genes identified through the mRNA transcriptome, along with the structure, provide a revealing insight into rice molecular response to salinity stress and underlie the salinity tolerance mechanism between genotypes.