PHYSIOLOGICAL RESPONSE OF SELECTED RICE ACCESSIONS TO SALINITY AND IN SILICO ANALYSIS OF DREB1A GENE AMONG DIPLOID Oryza SPECIES

Abstract

The responses of selected rice accessions to variant salt concentrations and in-silico analysis of DREB1A gene among diploid Oryza species were evaluated. Ten (10) rice accessions were selected based on their popularity in farmer's fields. Seedlings of each variety (one per pot) were watered with variant salt concentrations of 0mM, 100mM and 200mM for 21 days. The morpho-physiological characters (plant height, number of tillers, root length and dry weight) were evaluated using a standard evaluation system for rice. The reference sequences of OsDREB1A and AtDREB1A were used as queries to search against the 10 diploid Oryza species in the BLASTN of the PlantEnsembl database to reveal DREB1A orthologs. The retrieved DREB1A orthologs were used to compute the physicochemical properties of their proteins, gene motifs, intron-exon architecture and phylogenetic relationship. The studied accessions showed significant differences (p<0.05) in morpho-physiological responses to salinity. The accessions Zaqama, Yar-Garnaki, Yar-Yuti, Samira and Chana-Beru performed better under salt stress and there was no significant difference (p>0.05) between the control and salt-treated groups. Additionally, the in-silico analysis of DREB1A gene identified 10 orthologs with conserved single transcript, AP2 domain and unstable protein (characteristics of TFs) across the 10 diploid Oryza species. Phylogenetic analysis revealed 3 clusters of African rice and its progenitor, Asian rice and their relatives and O. brachyantha/O. punctata complex, similar to the evolution of rice species. Conclusively, salt stress affects rice in a concentration-dependent manner and DREB1A gene is a conserved plant transcription factor (TF) across diploid Oryza species.