Epiphytic yeasts as potential antagonists against Fusarium head blight of wheat (Triticum aestivum L.) caused by Fusarium graminearum sensu stricto

Abstract

Fusarium head blight (FHB), caused by Fusarium graminearum , is a significant disease of wheat in all wheat-growing areas. In this study, we screened a total of 344 yeast epiphytes isolated from cereal and weed plants against F. graminearum in vitro . Twelve potential antagonists were selected and subjected to in planta screening trials. In the in vitro bioassay trials, the highest average percentage inhibition of 64.31% (Isolate MGO2) was observed. The in vivo evaluation of the best 12 isolates showed a reduction in FHB severity and deoxynivalenol (DON) concentration of up to 15.62% (Isolate WL3) and 28.96% (Isolate SCH7), respectively. We observed a positive correlation between Area Under the Disease Progress Curve (AUDPC) and percentage seed infection. The 100-seed weight, however, was negatively correlated to both the AUDPC and the percentage seed infection. The best three yeast antagonists were selected based on AUDPC units, percentage seed infection, and 100-seed weight parameters and were identified as Papiliotrema flavescens (Isolates WL3 and WL6) and Pseudozyma sp. (Isolate MGO1) using 16S rRNA sequence analysis. These three yeast antagonists showed biocontrol efficacy against F . graminearum, and their incorporation in an integrated management programme could provide enhanced FHB control. To the best of our knowledge, this is the first report of yeast epiphytes isolated from Panicum maximum, and Ophiopogon japonicus tested as potential biological control agents against F. graminearum.