Physiological and molecular responses of a resistant and susceptible wheat cultivar to the fungal wheat pathogen Zymoseptoria tritici

Abstract

Background Zymoseptoria tritici is the causal agent of Septoria tritici blotch, one of the most economically destructive wheat foliar diseases. Here, we investigate the physiological and molecular changes triggered in two contrastingly responding wheat cultivars upon infection by Z. tritici. To accomplish this, we combined a qPCR with a targeted quantitative HPLC technique to evaluate the expression profiles of 13 defense-related genes and to profile the polyphenolic compounds induced differentially in two applied interactions. Results Our finding indicated that five out of 13 genes were strongly up-regulated in the resistant cultivar compared with that of the susceptible one at eight days post-inoculation (dpi), corresponding to the transition phase present in the infection process of Z. tritici. Additionally, our targeted HPLC analysis demonstrated that the traced phenolic compounds were highly elevated in the susceptible cultivar infected by Z. tritici compared with that of the resistant cultivar. Finally, our quantitative histopathological study showed that H2O2 accumulated in the resistant cultivar to a higher degree compared to the susceptible one at the biotrophic and switching phase. Conclusion To sum up, we conclude that Z. tritici mediates physiological and molecular alternations upon infection of wheat plants. Furthermore, the transition phase is likely a turning point in mounting incompatibility/compatibility in Z. tritici-wheat relationship, requiring further experiments to elucidate this claim in further detail.