Crucial Role of the Ca2+/CN Signaling Pathway in the Antifungal Activity of Seselin against Botrytis cinerea.

Botrytis cinerea causes gray mold in many fruit and vegetable crops. We previously found that Seselin (SL) displayed antifungal activity against B. cinerea (EC50 = 6.1 µg·mL-1), and this study investigated the effects of Ca2+ and the Ca2+/CN signaling pathway on its antifungal activity against B. cinerea. The results indicated that exogenous Ca2+, Cyclosporine A, and Verapamil reduced the sensitivity of SL against B. cinerea; SL significantly reduced the intracellular Ca2+ concentration in the hyphae; the sensitivity of strains ΔbcCCH1 and ΔbcMID1 to SL were significantly increased; and the expressions of CCH1, MID1, CNA, PMC1, and PMR1 genes of the Ca2+/CN signaling pathway were significantly downregulated by SL treatment. Hence, SL is a potential compound for developing fungicides against B. cinerea. SL dramatically reduces intracellular Ca2+ concentration and disturbs Ca2+ homeostasis, leading to cell death. The Ca2+/CN signaling pathway plays an important role in the antifungal activity of SL against B. cinerea.

Crucial role of Ca2+ /CN signalling pathway in the antifungal activity of disenecioyl-cis-khellactone against Botrytis cinerea.

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 [half maximal effective concentration (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 calcium ion/calcineurin (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. © 2022 Society of Chemical Industry.