TaWRKY10 transcription factor is a novel jasmonic acid signalling regulator involved in immunity against Septoria tritici blotch disease in wheat

Alberto Campanaro,Ed Byrne,Linda Millyard,Jack Lee,Angharad M R Gatehouse,Cunjin Zhang,Anjil K Srivastava,Ari Sadanandom

doi:10.1111/ppa.13388

Alberto Campanaro, Ed Byrne + Show 6 more

Open Access

https://doi.org/10.1111/ppa.13388

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Journal: Plant Pathology	Publication Date: May 25, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: Durham University, Newcastle University

Abstract

Septoria tritici blotch (STB), caused by the fungus Zymoseptoria tritici, is currently the main threat to worldwide wheat production in temperate climates. Understanding the genetic mechanisms that underpin the Z. tritici–wheat interaction will be crucial for generating new control strategies against STB. Plant hormones are essential regulators of growth and immunity. In particular, jasmonic acid (JA) plays a central role in defence against necrotrophic plant pathogens, but its role in mediating immunity against Z. tritici is largely unknown. Here we identify the transcription factor TaWRKY10 that is taxonomically restricted to the grass subfamily Pooideae as a novel regulator of JA responses in wheat. We demonstrate by using virus‐induced gene silencing that silencing TaWRKY10 leads to increased resistance against Z. tritici with an earlier onset of necrotic symptoms, but with reduced pathogen sporulation. Wheat plants silenced for TaWRKY10 show an up‐regulated JA response. Transcriptional profiling of TaWRKY10 knock‐down plants indicates that it is a negative regulator of the JA receptor TaCOI1 gene expression. Our data indicate that TaWRKY10 down‐regulates JA responses, contributing to the susceptibility of wheat to Z. tritici. We postulate that manipulating TaWRKY10 may provide a strategy to boost STB resistance in wheat.

Highlights

Zymoseptoria tritici is the causal pathogen of Septoria tritici blotch (STB), one of the most threatening wheat foliar diseases across temperate regions, causing up to 40% yield loss if untreated with fungicide (Orton et al, 2011)
All elite wheat cultivars show varying degrees of susceptibly to Z. tritici, and STB is solely controlled by fungicide treatment
Outbreaks of fungicide-resistant strains of Z. tritici have become more prevalent, indicating that new control measures are vital for sustainable wheat production

Summary

| INTRODUCTION

Zymoseptoria tritici is the causal pathogen of Septoria tritici blotch (STB), one of the most threatening wheat foliar diseases across temperate regions, causing up to 40% yield loss if untreated with fungicide (Orton et al, 2011). JA-Ile is subsequently recognized by CORONATINE INSENSITIVE 1 (COI1)-JASMONATE ZIM DOMAIN (JAZ) co- receptor complexes and activates a signalling cascade for the induction of a series of defence genes that are expressed in response to wounding, insect herbivory, and necrotrophic pathogens (Balbi & Devoto, 2008). The characteristic feature of the WRKY transcription factor family is its highly conserved 60 amino acid long WRKY domain at the N-terminus and zinc-finger-like motif at the C-terminus (Bakshi & Oelmüller, 2014) These motifs enable WRKY transcription factors to bind with high affinity to a specific DNA cis-acting element, (C/T)TGAC(T/C), named the W box, on target gene promoters. To reveal any role of JA in Z. tritici–wheat interaction, we studied the susceptibility of two wheat cultivars, KWS Lili and KWS Santiago, to STB, and investigated the role of the regulator TaWRKY10 in defence against Z. tritici using a gene silencing approach

| MATERIALS AND METHODS

| RESULTS

Findings

| DISCUSSION