棉花内生真菌CEF-373菌株对棉花黄萎病的防效及其作用机理

为明确棉花内生真菌CEF-373菌株对棉花黄萎病的防效及其作用机理,利用圆盘滤膜法和平板对扣培养法测定菌株CEF-373对大丽轮枝菌Verticillium dahliae菌丝生长的抑制作用,测定其对棉花黄萎病的温室和田间防效,并通过活性氧含量及防御基因表达情况来分析其作用机理。结果表明,菌株CEF-373的挥发性代谢产物和非挥发性代谢产物对大丽轮枝菌菌丝的生长均有显著抑制作用,抑制率最高分别可达37.75%和100.00%。用1×107CFU/mL的菌株CEF-373分生孢子悬浮液灌根后,对棉花黄萎病的温室防效可达71.12%,用质量比为3%的菌株CEF-373固体菌剂拌土栽培后,对棉花黄萎病的温室防效可达62.74%,防治作用显著。菌株CEF-373的发酵液滴灌和微生物肥料处理40 d后,对棉花黄萎病的田间防效达到最大,分别为36.23%和27.71%,而在后期有所降低。菌株CEF-373可以诱导棉花叶片中细胞活性氧的爆发;且菌株CEF-373成功激活了苯丙氨酸解氨酶、过氧化物酶、多酚氧化酶、几丁质酶和病程相关蛋白基因PR10的表达,对大丽轮枝菌的侵染具有抵御作用。表明棉花内生真菌CEF-373菌株通过抑制大丽轮枝菌生长以及诱导寄主系统抗病性来有效防治棉花黄萎病,具有较好的生物防治应用前景。

Biological control effect and mechanism of cotton endophytic fungus Fusarium solani CEF-373 against Verticillium wilt in Gossypium hirsutum

In order to determine the control effect and mechanism of cotton endophytic fungus CEF-373 on Verticillium wilt, the inhibition rate of strain CEF-373 against Verticillium dahliae was assessed using the exudate filtering method and plate-to-plate culture method, and the control effect of Verticillium wilt on cotton was tested with greenhouse and field experiments. Meanwhile, the content of reactive oxygen species and the expression of defense genes were detected to analyze the mechanism of action. The results showed that the growth inhibition rates of volatile metabolites and non-volatile metabolites of strain CEF-373 were up to 37.75% and 100.00% respectively. After root irrigation with 1×10⁷ CFU/mL strain CEF-373 conidia suspension, the greenhouse control efficiency on Verticillium wilt of cotton was up to 71.12%, and the solid bacterial strain CEF-373 with a mass ratio of 3% was mixed with soil and cultivated, the greenhouse control efficiency was up to 62.74%, which had a significant control effect on Verticillium wilt. The field control efficiency of strain CEF-373 on Verticillium wilt of cotton was maximized by drip irrigation and microbial fertilizer treatment for 40 days, which was 36.23% and 27.71% respectively, but decreased in the later stage. Strain CEF-373 could induce the outbreak of reactive oxygen species in cells of cotton leaves, and successfully activated the expression of phenylalanine aminolytic enzyme, peroxidase, polyphenol oxidase, chitinase and pathogenesis-related gene RP10, which had a protective effect against the infection of V. dahlia. The results indicated that strain CEF-373 of endophytic fungus in cotton could effectively control Verticillium wilt of cotton by inhibiting the growth of V. dahliae and inducing disease resistance of host, which has a good application prospect in biocontrol.