BREVIS RADIX is a plant specific gene family with unique protein-protein interaction domain. It regulates developmental processes viz. root elongation and tiller angle which are pertinent for crop improvement. In the present study, five BRX family genes were identified in wheat genome and clustered into five sub-groups. Phylogenetic and synteny analyses revealed evolutionary conservation among BRX proteins from monocot species. Expression analyses showed abundance of TaBRXL1 transcripts in vegetative and reproductive tissues except flag leaf. TaBRXL2, TaBRXL3 and TaBRXL4 showed differential, tissue specific and lower level expression as compared to TaBRXL1. TaBRXL5-A expressed exclusively in stamens. TaBRXL1 was upregulated under biotic stresses while TaBRXL2 expression was enhanced under abiotic stresses. TaBRXL2 and TaBRXL3 were upregulated by ABA and IAA in roots. In shoot, TaBRXL2 was upregulated by ABA while TaBRXL3 and TaBRXL4 were upregulated by IAA. Expression levels, tissue specificity and response time under different conditions suggest distinct as well as overlapping functions of TaBRX genes. This was also evident from global co-expression network of these genes. Further, TaBRX proteins exhibited homotypic and heterotypic interactions which corroborated with the role of BRX domain in protein-protein interaction. This study provides leads for functional characterization of TaBRX genes.
Keywords: Auxin; BRX; Brassinolide; Drought; Elongation; Wheat.
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