FaWRKY11 transcription factor positively regulates resistance to Botrytis cinerea in strawberry fruit

Plant WRKY transcriptional factors play an important role in responses to biotic and abiotic stresses and are involved in a wide range of resistance strategies against pathogen attacks. The present study investigated the functional role of FaWRKY11 in the regulation of defense responses to B. cinerea in strawberry fruit (Fragaria ananassa Duch. cv. Benihoppe). As strawberry fruits ripened and developed, FaWRKY11 expression levels gradually decreased and were closely related to the severity of B. cinerea. Transient transformation was conducted to overexpress and silence FaWRKY11 in strawberry fruits, which were later analyzed upon B. cinerea inoculation. The results indicated that 5 days following infestation with B. cinerea, the tissue damage of the fruits with overexpressed FaWRKY11 was significantly alleviated. The disease incidence was significantly lower that of the control. Conversely, the degree of damage suffered by the silenced fruit tissue increased to a certain extent, and the disease incidence was slightly higher than that of the control. The results revealed the positive regulatory function of FaWRKY11 in the resistance of strawberries against B. cinerea. Once the FaWRKY11 gene was overexpressed and silenced, the expression levels of the genes related to B. cinerea of the fruit were regulated to diverse extents. The most significant variations were observed in the expression levels of transcription factors related to disease resistance, and also in genes related to metabolism of phytohormones. Our study inferred that the FaWRKY11 might regulate the resistance of strawberries against B. cinerea through regulating some disease-resistance transcription factors and metabolic genes. Our study demonstrated the regulatory mechanism of FaWRKY11 regarding the defense in strawberries against B. cinerea.