Genome-wide identification, expression and bioinformatic analyses of GRAS transcription factor genes in rice

Our group has previously identified the activation tagging of a GRAS transcription factor (TF)gene in the gain-of-function mutant population of rice ( indica rice variety BPT 5204) screened for water use efficiency ([Moin et al, 2016][1]a). This family of GRAS transcription factors has been well known for their diverse roles in gibberellin signaling, light responses, root development, gametogenesis etc. Recent studies indicated their role in biotic and abiotic responses as well. Although this family of TFs received significant attention, not many genes were identified specifically for their roles in mediating stress tolerance in rice. Only OsGRAS23 (here named as OsGRAS22 ) was reported to code for a TF that induces drought tolerance in rice. In the present study, we have analyzed the expression patterns of rice GRAS TF genes under abiotic (NaCl and ABA treatments) and biotic (leaf samples infected with pathogens, Xanthomonas oryzae pv. oryzae that causes bacterial leaf blight and Rhizoctonia solani that causes sheath blight) stress conditions. In addition, their expression patterns were also analyzed in thirteen different developmental stages. We studied their spatio-temporal regulation and correlated them with in-silico studies. Fully annotated genomic sequences available in rice database have enabled us to study the protein properties, ligand interactions, domain analysis and presence of cis -regulatory elements in a bioinformatics analysis. Most of the genes were induced immediately after the onset of stress particularly in the roots of ABA treated plants. OsGRAS39 was found to be very highly expressive gene under sheath blight infection and both abiotic stress treatments while OsGRAS8 , OsSHR1 and OsSLR1 were also responsive. Our earlier functional characterization ([Moin et al., 2016][1]a) followed by the genome wide characterization of the GRAS gene family members in the present study clearly show that they are highly appropriate candidate genes for manipulating stress tolerance in rice and other crop plants. ### Competing Interest Statement The authors have declared no competing interest. [1]: #ref-25