我国西南地区主要谷物表面污染真菌的分离与分子鉴定

Separation and Molecular Identification of Fungal Contamination on Surfaces of Cereal Samples Collected in the Southwest of China

目的了解我国西南地区2014-2015年产主要谷物污染状况,探索谷物表面污染真菌的快速鉴定方法。方法利用孟加拉红培养基进行谷物表面真菌的分离与纯化。选用扩增真菌18S序列的通用引物ITS1和ITS4,通过PCR扩增和序列分析进行菌种鉴定。结果从157份谷物样品中分离得到277株真菌,利用分子生物学鉴定方法成功鉴定,污染率为42.0%,其中小麦主要侵染真菌为枝孢菌属、链孢霉属和小光腔菌属,玉米、大米主要侵染真菌为链孢霉属、曲霉菌属和青霉菌属。结论我国西南地区谷物样品的污染现象比较普遍,产毒菌株污染较为严重,存在潜在风险。选用的引物通用性较好,可用于谷物表面污染真菌的鉴定。

Objective To investigate the fungal contamination of cereal samples collected in the Southwest of China from 2014 to 2015and explore a rapid method for identifying the fungi of contaminating the cereal surfaces.Methods The Rose Bengal Medium was used to isolate and purify the fungi on the surfaces of cereal samples.The primers including ITS1 and ITS4were employed to amplify the fungal sequences of 18 Sand the polymerase chain reaction（PCR）and the sequence analysis was adopted to identify the strains.Results 277 fungal strains were obtained from the surfaces of 157 cereal samples and identified with the identification method of molecular biology,which showed that the contamination rate of the samples was 42.0%.The major contamination fungi of wheats were cladosporium spp.,neurospora spp.and leptosphaerulina chartarum spp.,and those of corns and grains were neurospora spp.,aspergillus spp.and penicillium spp.Conclusion The cereals are contaminated universally in the southwest of China.The contamination of toxicogenic strains is more serious,which brings about potential risks.The selected primers have strong universality and can be used to identify the fungi of contaminating the cereal surfaces.