高苇 杨利娟 刘春艳 张春祥 王勇

摘 要：为了从丰富的土壤微生物资源中挖掘对西瓜枯萎病有较高防效的生防菌株，通过梯度稀释和平板涂布法分离獲得西瓜根际土壤主要细菌，采用平板对峙培养和测定盆栽防效的方法，从中筛选出对西瓜枯萎病有较强拮抗活性的菌株，并通过菌落形态观察、生理生化鉴定、16S rDNA和gyrA基因序列比对获得生防菌株的分类地位。结果表明，从8份西瓜根际土壤中分离纯化到182个细菌单菌落，并筛选获得对西瓜枯萎病防效较高的3株拮抗细菌，接种30 d后盆栽防效均高于75%，与30%噁霉灵水剂防效无显著差异。综合形态特征、生理生化特性及序列分析结果，明确拮抗菌株JHXG0406为枯草芽胞杆菌（Bacillus subtilis），拮抗菌株JHXG0221和XQXG0111为解淀粉芽胞杆菌（Bacillus amyloliquefaciens）。获得了3株对西瓜枯萎病有较好防效的菌株，具有作为生防菌剂开发应用的潜力。

关键词：西瓜;枯萎病;拮抗细菌;防治效果;鉴定

中图分类号：S651+S436.5 文献标志码：A 文章编号：1673-2871（2021）01-019-05

Screening and identification biocontrol strain to watermelon Fusarium wilt

GAO Wei， YANG Lijuan， LIU Chunyan， ZHANG Chunxiang， WANG Yong

（Institute of Plant Protection， Chinese Academy of Agricultural Sciences， Tianjin 300384， China）

Abstract： The efficient antagonistic bacteria against watermelon Fusarium wilt were screened from rhizosphere soil. The bacteria in rhizosphere soil of watermelon were isolated by gradient dilution and spread， and antagonistic strains against watermelon Fusarium wilt were screened by confront culture and pot experiment. The taxonomic status was determined by colony morphology， physiological and biochemical identification， and 16S rDNA and gyrA gene sequencing. 182 bacterial colonies were isolated and purified from 8 watermelon rhizosphere soils. Three antagonistic strains with high control effect against watermelon Fusarium wilt were obtained. The control efficacy of three strains were above 75%， with no significant difference to 30% oxamyl aqueous solutions.The antagonistic JHXG0406 strain was identified as Bacillus subtilis， JHXG0221 and XQXG0111 were identified as Bacillus amyloliquefaciens. Three strains against watermelon Fusarium wilt were obtained in this study， which have potential as biocontrol agent for application.

Key words： Watermelon; Fusarium wilt; Antagonistic bacteria; Control efficiency; Identification

西瓜枯萎病是由尖孢镰刀菌西瓜专化型（Fusarium oxysporum f. sp. niveum）侵染所引起的、发生在西瓜上的病害，也是世界性范围的病害，一旦发生，很难防治，且随着栽培年限的增加逐年加重[1]。我国是世界上最重要的西瓜生产国和消费国[2]。近年来，随着设施栽培的迅速发展和优势产区的连年种植，连作障碍日益严重，西瓜枯萎病发病率不断升高，对西瓜产量和品质造成了极大的影响，限制了西瓜产业的可持续发展[3-4]。选育应用抗枯萎病的西瓜品种是西瓜枯萎病最安全有效的防控途径，但目前仍未发现对西瓜枯萎病免疫的西瓜种质资源[5-6]。……