京津冀设施大棚根际土壤中筛选出的防治根腐病的生防镰孢菌

 由致病性尖孢镰孢菌(Fusarium oxysporum)引起的根腐病严重危害果蔬生产,但非致病性镰孢菌可作为潜在的生防菌。为筛选防治根腐病的非致病生防镰孢菌,从京津冀设施大棚采集茄科、葫芦科果蔬78份根际土样中分离2 402株真菌,筛选出对致病性尖孢镰孢菌(F. oxysporum)具有拮抗效果的真菌173株。利用镰孢菌通用引物进行PCR扩增,从中筛选出28株候选镰孢菌;通过镰孢菌发酵液泡根进行安全性测试,筛选出对寄主黄瓜幼苗安全无害的镰孢菌菌株4株(1418、1441、1436和1473)。进一步通过镰孢菌测序通用引物TEF1αF/TEF1αR结合菌落和分生孢子的形态学特征,1418菌株和1441菌株被鉴定为尖孢镰孢菌(F. oxysporum)、1436菌株被鉴定为茄病镰孢菌(F. solani)。盆栽测试发现,除1441菌株外,1418菌株、1436菌株和1473菌株对黄瓜根腐病的防效均在50%以上,其中1418菌株的防效为70%,与杀菌剂咪酰胺的防效相当,具有很好的应用潜力。本研究筛选获得的具有生防潜力的镰孢菌不仅为镰孢菌致病力分化的研究提供了实验材料,也为新型生防产品的研制奠定了基础。

Screening and identification of nonpathogenic Fusarium spp. for biocontrol of root rot disease from Jing-Jin-Ji region

Root rot diseases caused by Fusarium oxysporum seriously decrease production of vegetables and fruits, whereas nonpathogenic Fusarium spp. could be used as potential biocontrol agents. In order to screen biocontrol nonpathogenic Fusarium spp., 78 soil samples were collected from the rhizosphere of Solanaceae and Cucurbitaceae vegetables and fruits in Beijing-Tianjin-Hebei (Jing-Jin-Ji) region, and 2 402 fungal strains were isolated. According to antagonistic effect assay against a pathogenic F. oxysporum strain, 173 strains with antagonistic effect against pathogenic F. oxysporum were screened out. Through specific PCR amplification with universal primers of Fusarium spp., 28 strains of Fusarium spp. with antagonistic effect were identified. Their safety to host plants was evaluated by soaking the cucumber seedlings (Zhongnong 18) in the fermentation suspension generated by the antagonistic strains, and four strains named 1418, 1441, 1436 and 1473 were confirmed to be nonpathogenic and harmless to cucumber seedlings. According to the combination of morphological characteristics of colony and conidia and Fusarium sequencing primer TEF1αF/TEF1αR, 1418 and 1441 strain were identified as F. oxysporum, and 1436 strain was identified as F. solani. Pot tests showed that except for 1441 strain, the control effects of 1418, 1436 and 1473 strain on root rot disease of cucumber seedlings were above 50%, while 1418 strain had the highest efficiency with the control effect at about 70%, which was nearly equivalent to that of commercial fungicide such as prochloraz. These results showed that 1418 strain had a good application potential to control root rot disease of cucumber seedlings. Our studies not only provided valuable experimental materials for further research on pathogenicity differentiation of Fusarium spp., but also laid the foundation for development of biocontrol products for root rot diseases.