Methyl jasmonate induced gene expression in wheat delays symptom development by the crown rot pathogen Fusarium pseudograminearum

Abstract

The necrotrophic fungal pathogen Fusarium pseudograminearum ( F. pseudograminearum) causes crown rot disease (CR) in wheat. This host–pathogen interaction has not been studied previously at the molecular level. In this study, using real-time quantitative PCR, the expression of 26 selected wheat genes was examined 1, 2 and 4 days after inoculation of wheat seedlings of the CR susceptible cultivar Kennedy and the partially field-resistant cultivar Sunco. Reproducible induction of eight defence genes consisting of PR1.1, PR2 ( β, 1‐ 3 glucanase), PR3 ( chitinase), PR4 ( wheatwin), PR5 ( thaumatin-like protein), TaPERO ( peroxidase), PR10 and TaGLP2a ( germin-like) was observed. These genes were induced in both cultivars, however, some genes were induced more rapidly in Sunco than in Kennedy. MJ treatment also induced the above pathogen responsive defence genes in both cultivars while benzo(1,2,3)thiadiazole-7-carbothionic acid S-methyl ester (BTH) treatment weakly induced them in Kennedy only. Similarly, treatment with MJ before inoculation significantly delayed the development of necrotic symptoms for 2 weeks in both wheat cultivars, while BTH pre-treatments delayed symptom development in Kennedy only. The chemically induced protection, therefore, correlated with induction of the F. pseudograminearum-responsive genes. These results support the emerging role of jasmonate signalling in defence against necrotrophic fungal pathogens in monocots and future manipulation of this pathway may improve CR resistance in wheat.