College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
Plant Dis. 2018 May;102(5):886-891. doi: 10.1094/PDIS-10-17-1602-RE. Epub 2018 Mar 5.
The ascomycete plant-pathogenic fungus Botrytis cinerea infects more than 1,400 plant species worldwide. Stimulatory effects of sublethal doses of fungicides on plant pathogens are of close relevance to disease management. In the present study, stimulatory effects of carbendazim on the virulence of B. cinerea to cucumber plants were investigated. Spraying carbendazim on cucumber plants at 3 to 200 μg/ml had stimulatory effects on the virulence of carbendazim-resistant isolates of B. cinerea and the maximum percent stimulations were 16.7 and 13.5% for isolates HBtom451 and HBstr491, respectively. Preconditioned mycelia (i.e., mycelia grown on potato dextrose agar [PDA] amended with carbendazim at concentrations of 10, 50, or 200 μg/ml) also showed increased virulence, and the maximum percent stimulations for isolates HBtom451 and HBstr491 were 7.9 and 9.5%, respectively. Compared with mycelia grown on PDA without carbendazim, virulence stimulation magnitudes of spraying carbendazim on leaves increased moderately but the concentrations of carbendazim that elicited the maximum stimulation increased 20- and 8-fold for preconditioned isolates HBtom451 and HBstr491, respectively. The time course of infection indicated that virulence stimulation was mediated by a direct stimulation mechanism. Studies of the physiological mechanism for stimulation demonstrated that carbendazim had no significant effects on tolerance to hydrogen peroxide, or on oxalic acid production in B. cinerea. These studies will deepen our understanding of quantitative features of hormetic effects of sublethal doses of fungicides on plant pathogens.
子囊菌植物病原真菌灰葡萄孢（Botrytis cinerea）可感染全球超过 1400 种植物。杀菌剂亚致死剂量对植物病原菌的刺激作用与病害管理密切相关。本研究调查了多菌灵对黄瓜植株灰葡萄孢致病力的刺激作用。在 3 至 200μg/ml 浓度下，多菌灵对灰葡萄孢抗多菌灵分离株的致病力具有刺激作用，HBtom451 和 HBstr491 分离株的最大刺激百分比分别为 16.7%和 13.5%。预处理菌丝（即在添加多菌灵浓度为 10、50 或 200μg/ml 的马铃薯葡萄糖琼脂[PDA]上生长的菌丝）也表现出增加的致病力，HBtom451 和 HBstr491 分离株的最大刺激百分比分别为 7.9%和 9.5%。与在不含多菌灵的 PDA 上生长的菌丝相比，叶片喷施多菌灵对致病力的刺激幅度略有增加，但对预处理分离株 HBtom451 和 HBstr491 产生最大刺激的多菌灵浓度分别增加了 20 倍和 8 倍。感染时间进程表明，致病力刺激是通过直接刺激机制介导的。对刺激生理机制的研究表明，多菌灵对灰葡萄孢耐受过氧化氢或产草酸没有显著影响。这些研究将加深我们对杀菌剂亚致死剂量对植物病原菌产生的激素效应定量特征的理解。
