草珊瑚炭疽病拮抗细菌的鉴定及其抑菌机理

Identification of antagonistic bacteria against anthracnose of Sarcandra glabra

【背景】草珊瑚炭疽病发生严重,目前尚未有植物内生细菌对该病原菌生物防治的研究报道。【目的】筛选对肿节风炭疽病Colletotrichumdematium具有拮抗作用的内生细菌,并对其抑菌机理进行研究。【方法】采用平板稀释法从广西不同地区采集健康肿节风植株的不同组织分离、纯化获得内生细菌。【结果】平板对峙试验结果表明,来自茎的RJ-4和JJ-5对草珊瑚炭疽病具有较强的拮抗作用,其中拮抗作用最强的菌株是RJ-4,其抑制率达到84.10%。抗菌谱测定结果表明,RJ-4、JJ-5对供试的14种病原真菌均有明显的拮抗效果,拮抗作用最强的是RJ-4,平均抑制率达到95.30%;抑菌机理研究结果表明,该菌株可以分泌蛋白酶和纤维素酶以及几丁质酶,破坏病菌菌丝,抑制病菌生长;含有拮抗细菌的发酵液对病原菌菌丝抑制明显,菌丝扭曲、断裂且分枝缠绕、菌丝颜色加深等。通过形态学特性和16S rRNA基因鉴定,RJ-4菌株为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。【结论】RJ-4菌株具有抑菌抗病功能,并能产生多种抗菌活性物质,这可为新型抗菌物质提供资源。

[Background]The anthrax of Sarcandra glabra was serious,so far there is no research report on the biological control of endophytic bacteria against this pathogen.[Objective]To screen out bacteria that have an antagonistic effect on Colletotrichum dematium,and to study its antibacterial mechanism.[Methods]Endophytic bacteria were isolated and purified from different tissues of healthy plants collected from different regions of Guangxi by the plate dilution method.[Results]The results of the plate confrontation test showed that RJ-4 and JJ-5 from stems had strong antagonistic effects on anthracnose of Sarcandra glabra.Among them,the strain with the strongest antagonistic effect was RJ-4,with an inhibition rate of 84.10%.The results of the antibacterial spectrum showed that RJ-4 and JJ-5 had obvious antagonistic effects on the 14 pathogenic fungi tested.The strongest antagonistic effect was RJ-4,with an average inhibition rate of 95.30%.It shows that the strain can secrete protease and cellulase and chitinase,destroy the mycelium of the pathogen,and inhibit the growth of the pathogen;The fermentation broth containing the antagonistic bacteria obviously inhibits the mycelium of the pathogen,and the mycelium is distorted,broken,and entangled,color deepens and so on.Based on morphological characteristics and 16 S rRNA gene identification,strain RJ-4 was Bacillus amyloliquefaciens.[Conclusion]Strain RJ-4 has bacteriostatic and disease-resistant functions and can produce a variety of antibacterial active substances,which can provide resources for new antibacterial substances.