A plant-derived small RNA shows potential for RNAi-based management of white mold in postharvest common bean

Common bean, an economically important vegetable crop, is severely threatened by white mold in both field and postharvest storage conditions. Sclerotinia sclerotiorum is a necrotrophic fungal pathogen that causes white mold on various vegetable and oilseed crops including common bean. Only a few methods for white mold control are available and new approaches are always desired. Small RNAs (sRNAs) play important roles in both onset of plant resistance and fungal pathogenesis, and have been explored to be used in RNA interference (RNAi) for disease management. In this study, an in silico analysis was conducted to identify plant-derived sRNAs in sclerotia of S. sclerotiorum . Among the identified sRNAs, one named ath-miR5658 exhibited differential expression during fungal development and infection. Suppressing ath-miR5658 via RNAi treatment revealed its important roles in sclerotial development and fungal infection. The function of ath-miR5658 was validated by the observation on a S. sclerotiorum strain generated through fungal subculturing, which exhibited reduced ath-miR5658 expression and impaired sclerotial development and fungal pathogenicity. Multi-omics analyses were conducted to further understand the potential regulatory impacts associated with ath-miR5658 reduction. The subculturing strain showed transcriptomic reprogramming relative to the wild-type, but did not exhibit detectable changes in the genome and proteome. This study reported for the first time a plant-derived sRNA associated with fungal development and pathogenicity in S. sclerotiorum , and demonstrates the RNAi-based application for sustainable management of white mold on postharvest common bean and other oilseed crops.