Insight into TaWRKYs transcription factors role during wheat growth and Septoria defense.

Abstract

Triticum aestivum is the major food source in many parts of the world, providing approximately 20% of calories consumed by humans. The pathogen Zymoseptoria tritici that causes Septoria Tritici Blotch (STB), is currently the main threat to wheat production, with an average yield loss of 20%. Therefore, understanding the molecular mechanisms that underpin the Septoria-wheat interaction will be crucial for generating new control strategies against STB. WRKY transcription factors are important components of signaling in plants, regulating many molecular mechanisms in response to abiotic and biotic stresses. Published data demonstrate that there are at least 3 wheat WRKYs (TaWRKY) that show altered expression upon Septoria infection. The hormone jasmonic acid (JA) plays key role in biotic stress response, but also in a diverse array of plant processes including development, reproduction, and response to abiotic stress. Most of our understanding of the JA signaling pathway derives from the dicot model plant Arabidopsis thaliana, while corresponding knowledge in wheat is somewhat limited.
Via bioinformatics analysis we identified TaWRKY10 and TaWRKY13 genes in wheat and validated the role of two of them during Septoria infection response. Moreover we have been able to demonstrate that TaWRKY10 is a key component of the JA signalling pathway. We specifically identified its role and downstream targets, as well as 6 putative regulators of its transcription. TaWRKY10 acting at the JA perception level couples growth and immunity. As growth and immunity are inversely correlated, investigating the molecular basis of their correlation could lead to the discovery of novel breeding tools.