2,4-表油菜素内酯对葡萄果实采后灰霉病的抑制作用机理

Modes of Action of 2,4-Epibrassionolide against Postharvest Gray Mold Decay of Grapes

为研究2,4-表油菜素内酯(2,4-epibrassionolide,EBR)处理对‘巨峰’葡萄果实采后灰霉病的抑制效果及作用机制,将葡萄果实经5μmol/L EBR溶液处理12 h后刺伤接种灰葡萄孢(Botrytis cinerea)病原菌,然后置于25℃下贮藏60 h。结果显示:EBR处理有效抑制了葡萄采后灰霉病的发生和病斑直径的扩展,与单一接种病原菌和EBR处理相比,先用EBR处理后接种B. cinerea葡萄果实展现出更强、更快的抗病反应,表现为几丁质酶、β-1,3-葡聚糖酶和苯丙氨酸解氨酶等抗病相关酶活力及总酚含量显著提高(P<0.05),H2O2积累及超氧化物歧化酶、过氧化氢酶、抗坏血酸过氧化物酶活力提高,同时VvCHI、VvGNS和VvPAL-like抗病基因表达显著增加(P<0.05);体外实验发现,EBR处理可显著抑制B. cinerea孢子的萌发,但对芽管伸长长度没有显著影响。结论:EBR处理主要是通过敏化反应机制诱导提高葡萄果实的抗病性,从而减轻灰霉病的发生。

The inhibitory effect of 2,4-epibrassionolide(EBR) treatment on gray mold disease caused by Botrytis cinerea in postharvest grape berries(Vitis vinifera L.× V. labrusca L. cv.‘Kyoho’) and the possible mechanisms were investigated.Grapes were pretreated with 5 μmol/L EBR for 12 h, inoculated with B. cinerea, and then stored at 25 ℃ for 60 h. The results showed that EBR treatment effectively inhibited the occurrence of gray mold and the expansion of lesion diameter.Grapes pre-treated with EBR showed stronger and faster response to the challenge of pathogen inoculation compared with either treatment alone, which corresponded to a significant increase in the activities of defense-related enzymes including chitinase,β-1,3-glucanase, phenylalanine ammonia-lyase as well as total phenols content(P < 0.05), the accumulation of H2 O2 and higher activities of superoxide dismutase, catalase, ascorbate peroxidase, and significantly increased expression levels of defense-related genes like VvCHI、VvGNS and VvPAL-like(P < 0.05). In vitro experiment showed that EBR treatment could inhibit spore germination but had no influence on germ tube elongation of B. cinerea. These results suggest that EBR treatment can improve resistance against gray mold decay in grapes, which is closely associated with the priming of defense responses.