Function of the endophytic fungus Acrophialophora jodhpurensis, methionine, and nitric oxide in wheat resistance induction against Fusarium graminearum via interplay of reactive oxygen species and iron

In this study, the effect of Acrophialophora jodhpurensis, methionine, and sodium nitroprusside (as a NO donor) in induction of resistance against Fusarium graminearum, as a hemibiotrophic phytopathogenic fungus causing wheat root and crown rot, was investigated in vivo. Also, the effect of A. jodhpurensis was investigated on the mycelial growth, spore germination and hyphal structures of F. graminearum in vitro. The obtained results showed that A. jodhpurensis reduced mycelial growth and spore germination of the pathogen. Also, the spores and hyphae of the pathogen were swollen and deformed in the presence of A. jodhpurensis. Wheat root colonization by A. jodhpurensis and foliar application of methionine and sodium nitroprusside reduced the disease severity of F. graminearum and increased the plant growth parameters, such as shoot and root weight compared to the controls. Application of A. jodhpurensis, methionine and sodium nitroprusside had a significant effect in induction of resistance against F. graminearum via increasing superoxide (O-2(center dot-)), hydrogen peroxide (H2O2), iron ions, phenolic contents, induction of antioxidant enzymes such as catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities, membrane stability index (MSI) and relative water content (RWC) compared to the plants only inoculated with F. graminearum and uninoculated controls. Simultaneous application of A. jodhpurensis and sodium nitroprusside was more effective than simultaneous application of A. jodhpurensis and methionine. Also, simultaneous application of A. jodhpurensis, methionine and sodium nitroprusside treatments showed more effect on the plant growth parameters and resistance induction against the pathogen compared to the other treatments. Therefore, the combined A. jodhpurensis, methionine and sodium nitroprusside treatment can be used for increasing the plant growth parameters and protecting wheat plants against F. graminearum.

Automated summary

This study investigated the effect of Acrophialophora jodhpurensis, methionine, and sodium nitroprusside in inducing resistance against Fusarium graminearum, a hemibiotrophic phytopathogenic fungus causing wheat root and crown rot. The results showed that A. jodhpurensis reduced mycelial growth and spore germination of the pathogen, and also affected its structural morphology. Wheat plants treated with A. jodhpurensis, methionine, and sodium nitroprusside showed increased resistance against F. graminearum and improved growth parameters compared to control plants. The combined treatment of A. jodhpurensis, methionine, and sodium nitroprusside was more effective in enhancing plant growth and protecting wheat plants against F. graminearum.