LAUSR

BACKGROUND Botrytis cinerea causes grey mould and is one of the most destructive fungal pathogens affecting important fruit and vegetable crops. In preliminary studies, we found that Disenecioyl-cis-Khellactone(DK) had strong antifungal activity against several fungi species including B. cinerea (EC50 =11.0 μg·mL-1 ). In this study, we aimed to further evaluate the antifungal activity of DK against B. cinerea and determine the role of Ca2+ /CN signalling pathway on its antifungal effect. RESULTS DK was effective against B. cinerea in both in vitro and in vivo assays. Exogenous Ca2+ reduced the antifungal activity of DK. The combination of DK and cyclosporine A (CsA) did not exhibit an additive effect against B. cinerea. In contrast to CsA, DK reduced the intracellular Ca2+ concentration in B. cinerea. DK bound to calcineurin A (cnA) and up-regulated the expression of PMC1 and PMR1 genes. Moreover, DK sensitivity of △bccnA significantly decreased compared with that of Bc05.10 strain. CONCLUSION DK is a promising lead compound for developing fungicides against B. cinerea. The Ca2+ /CN signalling pathway plays a crucial role in the DK antifungal activity, and cnA is one of the targets of DK against B. cinerea. DK directly reacts with cnA, which up-regulates the transcription of Ca2+ /CN-dependent target genes PMC1 and PMR1, decreasing the intracellular Ca2+ concentration and disturbing the intracellular Ca2+ balance, leading to cell death. This article is protected by copyright. All rights reserved.