Génétique héréditaire : recherche actuelle

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Studies on Molecular Characterization of DREB Gene in Indica Rice (Oryza sativa L.)

Jadhao KR, Samal KC, Pradhan SK and Rout GR

Number of potential candidate genes (CGs) has been identified by transcriptome and transgenic approaches involved in the adaptive responses to drought in cereals. One of these genes conferring tolerance to drought is DREB gene family. The exploration of genetic/allelic variation within the DREB gene family is an important prerequisite towards a better understanding of stress tolerance. The present investigation aims to study allelic variation in nucleotide sequence within DREB gene of different rice cultivars need for crop improvement programme. Ten upland as well as lowland rice cultivars was used for molecular characterization and allele mining. The results showed that the DREB gene was found in all the tested germplasm and submitted to NCBI GenBank (accession numbers KF 545561 to KF 545569). Bioinformatics analysis showed that 100 percent identity with AP2 DNA binding domain of 59 amino acids which showed conserved three sheets with 14th valine and 19th glutamic acid conserved residues. AP2 domain of putative DREB protein were found rich in alanine (17.6%) and arginine (15.7%) amino acids with a predicted molecular mass of 5.89 kDa and iso-elecric point (pI) 10.38. It is observed that DREB gene nucleotide sequences were verified with DNA polymorphism analysis, out of which 196 invariable (monomorphic) and 8 variable (polymorphic) i.e. segregating sites were identified including 9 number of mutation and 5 haplotypes. The haplotypes (gene) diversity was 0.756; the variance and standard deviation diversity were 0.01678 and 0.130 respectively. The result showed that the variety ‘Khandagiri’ showed 97.5% similarity with all accessions DREB gene of rice and 0.036% evolutionary divergence with AK121956 accession present in the database. This might have enhanced the capability of DREB gene as a transcription factor and that lead to provide better adoption and tolerance capability of the cultivar during drought.