玉米穗腐病菌的拮抗菌筛选、鉴定及降解DON毒素能力测定

穗腐病是玉米生产上的重要病害，在造成产量损失的同时，产生的毒素严重危害人畜健康。为获得兼具降解毒素功能的玉米穗腐病菌的生防菌株，以脱氧雪腐镰刀菌烯醇（deoxynivalenol，DON）毒素为靶标，从玉米病穗上分离筛选到一株能够降解该毒素的细菌菌株TP，经菌落形态特征、结合16S rDNA和gyrB基因序列分析，初步鉴定为贝莱斯芽胞杆菌Bacillus velezensis。对峙试验和复筛共培养结果显示，菌株TP对禾谷镰孢F18的抑制率分别达到70.63%和99.5%。经HPLC检测，TP在含DON的无机盐溶液中培养10 d后，其对DON的降解率为98.97%。以上研究结果表明，贝莱斯芽胞杆菌TP能拮抗禾谷镰孢菌，且能高效降解DON毒素，该菌株在防治禾谷镰孢菌引起的玉米穗腐病以及降低毒素危害中具有广阔的应用前景。

Screening and Identification of Antagonistic Bacteria of Maize Ear Rot and Its Degradation Effect on DON

Ear rot is an important disease in maize agricultural production. While causing yield loss, the toxins produced by the pathogens bring serious harms to human and animal health. In order to obtain the biocontrol strain against maize ear rot with the function of degrading toxins, DON was used as the target, and a bacterial strain TP capable of degrading this toxin was isolated and screened from maize diseased ears in field. Based on colony morphology and 16S rDNA and gyrB gene sequence analysis, the strain TP was identified as Bacillus velezensis. Confrontation and cocultivation tests showed that the inhibition rates of TP against Fusarium graminearum F18 reached 70.63% and 99.5%, respectively. After the strain TP was cultured in the inorganic salts solution containing DON for 10 days, the degradation rate of DON was 98.97%. The above results showed that the strain TP could inhibit the growth of F. graminearum F18 and degrade DON efficiently. It has a promising application prospects in controlling maize ear rot and reducing the derived toxin hazard caused by F. graminearum.