肿节风炭疽病拮抗真菌筛选及作用机理研究

Screening and mechanism of fungi antagonistic to Colletotrichum dematium of Sarcandra glabra(Thunb.)

【目的】筛选肿节风炭疽菌(Colletotrichum dematium)拮抗真菌,为肿节风炭疽病的生物防治提供科学依据。【方法】采用平板稀释法和平板对峙法从肿节风主产区广西靖西市和都安县健康肿节风根系土壤中筛选出对肿节风炭疽病菌及14种其他植物病原真菌具有较强抑制作用的真菌,采用ELISA试剂盒测定拮抗真菌无菌发酵液中的蛋白酶、纤维素酶和几丁质酶含量,综合平板对峙培养、抑菌谱及产酶能力选取综合表现最优的拮抗菌株;基于形态学和分子生物学特征对拮抗菌株进行鉴定。【结果】平板对峙试验结果表明,菌株JT-8、JT-3和DT-5对肿节风炭疽病菌具有较强的拮抗作用,其中拮抗作用最强的菌株是JT-8,对炭疽病菌的抑制率达91.57%。抗菌谱测定结果表明,菌株JT-8、JT-3和DT-5对供试14种病原真菌均有明显的拮抗作用,其中拮抗作用最强的为菌株JT-8,平均抑制率达89.88%,该菌株可产生几丁质酶、纤维素酶和蛋白酶,可抑制炭疽病菌菌丝生长,病原菌菌丝表现为扭曲、断裂、分支缠绕和颜色加深等。通过形态学观察和ITS测序鉴定,确定菌株JT-8为淡紫紫孢菌(Purpureocillium lilacinum)。【结论】淡紫紫孢菌对肿节风炭疽病病原菌具有强拮抗作用,能产生多种抗菌活性物质,且广谱抑菌,具有较好的生防开发潜能。

【Objective】Screening Colletotrichum dematium antagonistic fungi of Sarcandra glabra to provide scientific basis for biological control for S.glabra anthracnose.【Method】The fungi with strong inhibitory effect on the anthracnose of S.glabra and 14 other plant pathogenic fungi were screened by plate dilution method and plate confrontation method from the health root soil of S.glabra producing areas,Jingxi and Du’an of Guangxi.ELISA kit was used to determine the content of protease,cellulase and chitinase in the aseptic fermentation broth of antagonistic fungi,antagonistic strains with the best comprehensive performance were selected from the plate confrontation culture,antifungal spectrum and enzyme production ability.Antagonistic strains were identified based on morphological and molecular biological characteristics.【Result】By plate confrontation test,the results showed that the strains JT-8,JT-3 and DT-5 had antagonistic effect against anthracnose of S.glabra,strain JT-8 had the highest antagonistic effect and antagonism rate was 91.57%.Antifungal spectrum tests showed that strains JT-8,JT-3 and DT-5 had antagonistic activities against 14 plant pathogens,JT-8 had the strongest antagonistic activity and antagonism rate was 89.88%.The result of antibiosis mechanism indicated that three strains could produce chitinase,cellulose and protease to inhibit growth of anthracnose bacteria,and the mycelia showed distorted,fractured,with increased and winding branches and deepened color.Based on morphological and ITS rDNA sequence analysis,strain JT-8 was identified as Purpureocillium lilacinum.【Conclusion】P.lilacinum has strong antagonistic effects against anthracnose of S.glabra,it can produce a variety of antibacterial substances which have broad spectrum bacteriostatic activity.Therefore it has good potential for biological control development and prevention.