红树内生细菌菌株Kc-38的抗菌物质及对采后芒果炭疽病的防效

Antibiotic Substances Produced by Mangrove Endophytic Bacteria Kc-38 and Biocontrol Efficacy on Anthracnose of Postharvest Mangoes

Kc-38菌株是本实验室从红树植物秋茄Kandelia candel体内分离得到的内生细菌,对峙生长法测定发现该菌株对芒果炭疽病菌Colletotrichum gloeosporioides和枯萎病菌Fusarium oxysporum等多种植物病原菌具有较强的抑制作用。根据菌体形态、培养特性、生理生化反应及16SrDNA序列分析将该菌株初步鉴定为解淀粉芽孢杆菌Bacillus amyloliquefaciens。该菌株对芒果炭疽病具有良好的防效,用菌株发酵液及发酵上清液处理9d后,对采后芒果炭疽病的防效分别达到65.12%和62.79%。进一步研究表明,其分泌的胞外抗菌物质为一类对热稳定和抗紫外照射的蛋白类物质,在pH2.0～11.0范围内均具有抑菌作用,以pH2.0～8.0范围内的抗菌活性较强。

The endophytic bacterial strain Kc-38 isolated from the tissue of Kandelia candel had strong inhibitory activity against many plant pathogenic fungi,such as Colletotrichum gloeosporioides,Fusarium oxysporum,and so on.According to the morphological,physiological and biochemical characteristics,and 16S rDNA sequence analysis,strain Kc-38 was identified as Bacillus amyloliquefaciens. The strain effectively suppressed mango anthracnose disease caused by C.gloeosporioides.When tested on postharvest mango fruits and treated with the bacterial suspension and its cellular exudates,the control efficacy on the 9th d reached 65.12% and 62.79%,respectively.Further studies showed that the antibiotic substances produced by the strain were some kind of antifungal proteins.The proteins were demonstrated to be UV-tolerant,thermostable and inhibitory at pH value ranged from 2.0 to 11.0,but more inhibitory at pH 2.0-8.0 than at pH9.0-11.0.