Rice Genomics Tools Reveal a WRKY53 Transcriptional Network in Wheat

The transcription factor WRKY53 is induced by various stresses in cereals. Although essential to the aphid resistance response of wheat, very little is known about the structure, function and regulation of the wheat ortholog, TaWRKY53. Sequencing the ORF and 1.2 kb promoter region of TaWRKY53 revealed structural similarities shared with the rice ortholog, OsWRKY53, suggesting conservation of function. Therefore, we employed bioinformatic and functional genomics tools developed for rice to determine genetic components of the TaWRKY53 transcriptional network. Based on rice gene coexpression networks and the presence of W-boxes in their 1 kb promoter regions, we selected a chitinase, a peroxidase and a receptor kinase as likely downstream targets of WRKY53, and tested the ability of recombinant TaWRKY53 protein to interact with these rice promoters. To discover novel protein-protein interactions involving TaWRKY53, we performed yeast two-hybrid analyses using a rice cDNA library enriched for pathogen-responsive genes. A microsomal glutathione S-transferase showed a strong interaction with the TaWRKY53 protein, offering further support for the regulatory role of TaWRKY53 during the oxidative burst. Using a yeast one-hybrid approach to find novel proteins able to interact with the promoter region of TaWRKY53, we discovered a calmodulin-related calcium sensor protein, an ultraviolet-B repressible protein and a DUF584 protein as possible upstream regulators of the WRKY53 network. Collectively, our data suggest that TaWRKY53 acts as a transcriptional regulator of several defense-related pathways in wheat.