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为寻找对杧果炭疽菌Colletotrichum gloeosporioides有效的生防菌株,从瓜叶白粉病病斑上分离得到104株细菌,通过平板对峙培养筛选出16株拮抗细菌,分别测定其在8种不同培养基中的抑菌活性,筛选出有较强抑菌作用的9A、26A和4N菌株进行室内、果园防病试验,并对具有较好防治作用的9A、26A菌株进行了鉴定。结果显示,拮抗菌9A、26A和4N分别在南瓜汁、红薯汁和马铃薯汁培养基上的抑菌活性最高,对杧果炭疽菌菌丝生长抑制率分别为88.83%、87.83%和85.87%;室内9A、26A和4N菌株菌液处理离体果实,24 h后接种炭疽菌分生孢子液,对杧果炭疽病的防治效果均达100%,与咪鲜胺对照组相同;在果园9A和26A的防病效果分别为98.4%和90.5%,显著高于对照组的防效78.8%,而4N的防效只有58.2%。根据形态、生理生化特征及16S rDNA序列分析结果,将菌株9A和26A鉴定为枯草芽胞杆菌Bacillus subtilis。研究表明,菌株9A和26A具有较好的生防利用价值。
In order to find an effective biocontrol strain against Colletotrichum gloeosporioides, 104 strains of bacteria were isolated from the powdery mildew of melon leaves and 16 strains of antagonistic bacteria were screened by plate confrontation culture. The antagonistic bacteria were determined in 8 different media The strains 9A, 26A and 4N with strong antibacterial activity were screened for indoor and orchard disease control. The strains 9A and 26A with good anti-bacterial activity were also identified. The results showed that the antibacterial activities of antagonistic bacteria 9A, 26A and 4N were the highest in pumpkin juice, sweet potato juice and potato juice medium, respectively. The inhibitory rates of antagonistic fungi 9A, 26A and 4N were 88.83%, 87.83% and 85.87%, respectively. After inoculation with inoculum of strains 9A, 26A and 4N in vitro, the inoculation of conidia of anthracnose after 24 h achieved 100% control effect on anthracnose of fruit flesh, which was the same as prochloraz; The anti-disease effects of 26A were 98.4% and 90.5%, respectively, which were significantly higher than those of the control group (78.8%), while those of 4N were only 58.2%. According to morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis, strains 9A and 26A were identified as Bacillus subtilis. Studies have shown that strains 9A and 26A have good biocontrol value.