Wheat bHLH transcription factor gene, TabHLH060, enhances susceptibility of transgenic Arabidopsis thaliana to Pseudomonas syringae

• We cloned a novel bHLH transcription factor TabHLH060.
• Fluorescently labeled TabHLH060 was localized at the nucleus.
• The Y2H yeast system showed TabHLH060 with transactivation activity.
• Overexpression of TabHLH060 enhanced disease susceptibility.
• Possible roles of TabHLH060 protein involved in defense responses are discussed.

Plant bHLH transcription factors have important roles in regulation of developmental processes and responses to environmental stresses, but little is known about their functions in wheat in response to infection by pathogens. A new bHLH-type gene TabHLH060 was cloned from bread wheat (Triticum aestivum) and characterized. TabHLH060 was strongly expressed in wheat leaves and involved in response to infection by the obligate pathogen Puccinia striiformis f. sp. tritici. Treatments with defense-related hormones salicylic acid, methyl jasmonate and particularly ethylene suppressed the transcription level of TabHLH060 to different extents. Susceptibility of TabHLH060-overexpressing Arabidopsis plants to Pseudomonas syringae DC3000 was significantly enhanced. TabHLH060 overexpression resulted in suppression of transcription levels of resistance-related genes PR1, PR2 and PR5 involved in SA signaling pathway, but enhanced genes PDF1.2 and ORA59 involved in the jasmonic acid and ethylene signaling pathways. TabHLH060 is a novel bHLH member of the Ⅳc subgroup, and negatively regulates plant disease resistance through jasmonic acid and ethylene signaling.