FaSnRK1α mediates salicylic acid pathways to enhance strawberry resistance to Botrytis cinerea

Strawberry is a major fruit crop worldwide because its nutritional and health benefits to human health, but its productivity is limited by Botrytis cinerea. Sucrose nonfermentation 1-related protein kinase 1 (SnRK1) has a defense function against pathogens, but the function of SnRK1 in the defense response to B. cinerea in plants is still unclear. In this study, FaSnRK1α-OE and RNAi fruits were constructed and then inoculated with B. cinerea. The result reveals a positive role of FaSnRK1α in the regulation of resistance to gray mold. FaSnRK1α affects SA content by regulating FaPAL1 and FaPAL2 expressions. The genes related to the SA signaling pathway (FaTGA1 and FaTGA2.1) were significantly increased/decreased in FaSnRK1α-OE or FaSnRK1α-RNAi fruit, respectively. FaSnRK1α interacted with the FaWRKY33.2 protein and negatively regulated FaWRKY33.2 expression, and FaWRKY33.2 acts as a repressor of disease resistance to B. cinerea. Finally, FaSnRK1α regulates the expression of six PR genes and the activities of antioxidant enzymes to boost defense response after B. cinerea inoculation. Our findings showed that FaSnRK1α increases the resistance of strawberry fruit to B. cinerea via SA signaling pathway and interaction with the FaWRKY33.2 transcription factor.