In silico characterization, and expression analysis of rice golden 2-like (OsGLK) members in response to low phosphorous

The availability of phosphorus (P) affects productivity of rice. Under acidic soil conditions (pH < 5.5), P is rapidly immobilized in the soil. Several transcription factors play an important role in low Pi tolerance response, including MYB family members but their role in acidic soil is yet unknown. In this study, genome wide identification and characterization of golden 2-like (GLK) members belonging to GARP superfamily from rice (OsGLK) led to identification of 46 members distributed over 12 chromosomes. We assigned gene nomenclature, analyzed gene structure and identified mutant orthologs and phenotypes in maize and rice, respectively. On the basis of biological functions three categories viz., (a) two-component response regulator (five members), (b) putative transcription factor (21 members) and (c) phosphate starvation response (8 members) were identified. Phylogenetic analysis revealed a total of nine subgroups with MYB homeodomain-like and MYB CC-type domains conserved across members. Expression profiling of OsGLKs in response to 24 and 48 h of low Pi in four contrasting rice genotypes, revealed significantly higher expression of OsGLK10, OsGLK15, OsGLK22 and OsGLK30 in tolerant genotypes as compared to susceptible genotypes, suggesting their role in Pi starvation tolerance. Meta analyses and cis-regulatory elements (CREs) profiling of OsGLK showed diverse expression pattern in various tissues and organs and also modulation in response to various abiotic and biotic stresses. Our results highlight the versatile role of this diverse and complex GLK family, in particular to abiotic stress. These genes will form the basis of future studies on low Pi tolerance in acidic soils.