2A型蛋白磷酸酶对玉米大斑病菌菌体发育的调控作用

Effects of 2A Type Protein Phosphatase on the Development of Setosphaeria turcica

【目的】明确2A型蛋白磷酸酶(PP2A)在玉米大斑病菌致病过程中的作用,为研发新型杀真菌制剂和探讨植物病害防治新策略奠定理论基础。【方法】利用不同浓度的PP2A特异性抑制剂——斑蝥素(cantharidin)处理玉米大斑病菌,研究在该抑制剂作用下玉米大斑病菌的菌落生长、分生孢子产量、孢子萌发、附着胞发育、黑色素合成及HT-毒素活性。【结果】随着斑蝥素浓度的增加,其对菌丝体生长的抑制作用也逐渐增强,当达到160μmol.L-1时,培养8 d的菌落平均直径仅为对照的41.7%;同时,处理组产孢量均高于对照组,160μmol.L-1斑蝥素处理组产孢量达到了对照组的15.5倍。分析斑蝥素对病菌分生孢子的萌发、附着胞形成及侵染的影响表明,上述3个阶段对斑蝥素的敏感性由强到弱依次为附着胞形成>分生孢子萌发>附着胞侵染;此外,对照组的胞内黑色素含量为0.13 g.L-1,处理组的胞内黑色素含量均高于对照组,且随着斑蝥素浓度的增加不断升高。【结论】PP2A特异性抑制剂斑蝥素对玉米大斑病菌菌落生长、附着胞发育具有抑制作用,而对分生孢子产生及胞内黑色素的合成具有一定的促进作用。

[Objective] The aim of this research is to preliminarily explore the function of type 2A phosphoprotein phosphatase （PP2A） in regulating the development and pathogenicity of S. turcica with the usage of cantharidin, the specific inhibitor of PP2A, and lay a theoretical foundation in researching the new antifungal agents and the prevention of plant diseases. [Method] S. turcica was treated with cantharidin at different concentrations to observe and investigate colony growth, conidial yield, conidial germination, appressorium production, melanin biosynthesis and HT-toxin activity of the pathogen. [Result] The higher the concentration of cantharidin was, the more strongly the hyphal growth of S. turcica was inhibited. The diameter of 8-day-old colony on the PDA media with cantharidin of 160 Ixrnol.L1 was 41.7% of that of the mock. Meanwhile, the conidial production in treated groups was higher than that of the CK. When the concentration of cantharidin was up to 160 μmol.L^-1, the conidial production was 15.5 times as many as that of the CK. The results of the influences of cantharidin on conidial germination, appressorial formation and invasion showed that the sensitivity of these developmental stages from high to low was appressorial formation 〉 conidial germination 〉 appressorial invasion. Furthermore, the contents of intracellular melanin in treated groups were all higher than that of the CK which was 0.13 g.L＂l, and the content of intracellular melanin was positive related with the concentration of cantharidin. [ Conclusion ]Cantharidin could significantly inhibit colony growth, conidial germination, appressorium production of S. turcica and promote conidiation and the biosynthesis of intracellular melanin.