Genome-wide identification and characterization of RWP-RK transcription factor family members in wheat (<i>Triticum aestivum</i> .L)

RWP-RK is a small family of transcription factors (TFs) that are exclusively found in plants. These TFs have a conserved RWP-RK motif which mediates DNA binding. These RWP-RK TFs have been classified in two subfamilies: (i) NLPs (NIN-like proteins), which carry an additional PB1 domain at their C-terminus along with the RWP-RK domain, and (ii) RKDs, which contain only RWP-RK domain. TFs from both these subfamilies are known to play a key role in regulating responses to nitrogen deficiency. In the present study, we carried out a genome-wide survey for genes encoding RWP-RK TFs using wheat genome sequences available at EnsemblPlants and identified 11 members of RWP-RK family. These 11 TFs include 6 NLPs and 5 RKDs. Gene Ontology (GO) term annotations revealed that these TFs play a key role in various biological processes including N metabolism. The proposed 3D structure of these TFs shared high homology with known structures and allowed us to understand their functions at the molecular level. In silico expression profiling of these putative RWP-RK genes in wheat suggested increased expression of three genes (TaNLP2, TaNLP3, and TaNLP4) under N starvation and drought stress. Further studies like VIGS and RNAi will elucidate the functional role of these wheat RWP-RK TFs in controlling cellular and tissue responses to N deficiency and drought stress.