Genome wide identification of Dof transcription factor gene family in sorghum and its comparative phylogenetic analysis with rice and Arabidopsis

The Dof (DNA binding with One Finger) family represents a classic zinc-finger transcription factors involved with multifarious roles exclusively in plants. There exists great diversity in terms of number of Dof genes observed in different crops. In current study, a total of 28 putative Dof genes have been predicted in silico from the recently available whole genome shotgun sequence of Sorghum bicolor (L.) Moench (with assigned accession numbers TPA:BK006983-BK007006 and TPA:BK007079-BK007082). The predicted SbDof genes are distributed on nine out of ten chromosomes of sorghum and most of these genes lack introns based on canonical intron/exon structure. Phylogenetic analysis of 28 SbDof proteins resulted in four subgroups constituting six clusters. The comparative phylogenetic analysis of these Dof proteins along with 30 rice and 36 Arabidopsis Dof proteins revealed six major groups similar to what has been observed earlier for rice and Arabidopsis. Motif analysis revealed the presence of conserved 50-52 amino acids Dof domain uniformly distributed across all the 28 Dof proteins of sorghum. The in silico cis-regulatory elements analysis of these SbDof genes suggested its diverse functions associated with light responsiveness, endosperm specific gene expression, hormone responsiveness, meristem specific expression and stress responsiveness.