Antibiotic substances produced by mangrove endophytic bacteria Kc-38 and biocontrol efficacy on anthracnose of postharvest mangoes.
Wang Yuan, Zhan RuLin, He Hong, LüZhuBin, Yu XiaoQin, Liang YongQi, Chen HongYu
Author Affiliation: Agricultural College of Guangdong Ocean University, Zhanjiang 524088, China.
Chinese Journal of Biological Control 27 : 82-87
Abstract : 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.