Engineered Phomopsis liquidambaris with Fhb1 and Fhb7 Enhances Resistance to Fusarium graminearum in Wheat

Fusarium head blight is one of the most serious diseases caused by Fusarium graminearum in wheat. Here, we developed a new way to prevent and control Fusarium head blight by introducing the resistance genes Fhb1 and Fhb7 into the endophytic fungus Phomopsis liquidambaris, named PL-Fhb1 and PL-Fhb7, respectively, which could colonize wheat. The wheat seedlings were preinoculated with PL-Fhb1 and PL-Fhb7 to enhance the resistance against deoxynivalenol (DON) and PL-Fhb1 and PL-Fhb7 inhibited the growth of F. graminearum by 73% and 49%, respectively. The incidence rate of diseased spikes decreased to 35.2% and 45.4%, and the corresponding DON levels for wheat grains decreased from 13.2 to 1.79 mu g/g and from 13.2 mu g/g to 0.39 mu g/g when the leaves were preinoculated with PL-Fhb1 and PL-Fhb7 after overwintering, respectively. The incidence rates of diseased spikes decreased to 25.7% and 34.7%, and the DON levels for wheat grains decreased from 17.48 mu g/g to 1.23 mu g/g and from 17.48 mu g/g to 0 mu g/g when the wheat flowers were inoculated with PL-Fhb1 and PL-Fhb7, and the wheat flowers were subsequently infected with F. graminearum, respectively. It was confirmed that DON was transformed into DON-glutathione (GSH) by PL-Fhb7 using high-performance liquid chromatography-mass spectrometry (HPLC-MS). However, PL-Fhb1 may have increased plant immunity and enhanced the resistance to F. graminearum. This study indicates that engineered endophytes can improve the resistance to Fusarium head blight and presents a new method for the biological control of Fusarium head blight.

Automated summary

In this study, the resistance genes Fhb1 and Fhb7 were introduced into the endophytic fungus Phomopsis liquidambaris to develop a new method for preventing and controlling Fusarium head blight in wheat. Preinoculation of wheat seedlings with PL-Fhb1 and PL-Fhb7 increased the resistance against deoxynivalenol (DON) and inhibited the growth of F. graminearum. The incidence rates of diseased spikes and the levels of DON in wheat grains were significantly reduced when preinoculating leaves with PL-Fhb1 and PL-Fhb7 or inoculating wheat flowers with PL-Fhb1 and PL-Fhb7 followed by F. graminearum infection. Furthermore, PL-Fhb7 was found to transform DON into DON-glutathione using HPLC-MS. This study highlights the potential of engineered endophytes for improving resistance to Fusarium head blight and presents a new approach for biological control.