余小兰　邹立飞　邹雨坤　李光义　李晓亮　李勤奋

摘要：【目的】筛选对甜瓜枯萎病菌有较强拮抗活性的菌株，并对拮抗菌株进行分类鉴定，为丰富热带地区甜瓜枯萎病生防菌资源库及田间应用提供参考。【方法】以前期筛选获得的82株菌株为试验材料，通过平板对峙、继代培养、发芽率及盆栽试验筛选出对甜瓜枯萎病菌有较强拮抗活性的菌株，并通过形态特征、生理生化特征及16S rDNA序列分析对筛选获得的菌株进行分类鉴定。【结果】筛选出一株对甜瓜枯萎病菌有较强拮抗活性的放线菌菌株D2，其对枯萎病的防治效果达73.53%。D2菌株可形成气生菌丝和孢子丝，孢子丝呈螺旋形，孢子卵呈圆形，且与利迪链霉菌（Streptomyces lydicus）聚于同一分支中，其同源性达99.6%；综合D2菌株的形态特征及生理生化特性，可鉴定其为利迪链霉菌（S. lydicus）。【结论】D2菌株对甜瓜枯萎病有较好的防治效果，具有开发成生物农药或生物肥料的潜力。

关键词： 甜瓜枯萎病；拮抗菌；筛选；鉴定；热带地区

中图分类号： S182 文献标志码：A 文章编号：2095-1191（2018）06-1118-07

Abstract：【Objective】Antagonistic bacteria with strong antagonistic effect to fusarium wilt of melon was screened and identified to provide reference for enriching the resources of biocontrol bacteria against melon fusarium wilt in tropical zone. 【Method】Eighty-two strains obtained in preliminary screening were used as experimental material， and antagonistic bacteria against melon fusarium wilt were screened by using plate confront culture， successive transfer culture， germination experiment and pot experiment.The strains were classified through characteristics in morphology， physiology and biochemistry and information of 16S rDNA. 【Result】A strain of actinomycetes D2 with strong antagonistic effect to melon fusarium wilt was screened and it had 73.53% control efficiency to fusarium wit of muskmelon. Strain D2 would form aerial hyphae and fibrillae of spores， and fibrillae of spores were spiral， and spore eggs were round. Strain D2 and Streptomyces lydicus were clustered in the same branch with 99.6% homology. Taking the morphological characters and physiological and biochemical characters of strain D2 into consideration， strain D2 was finally identified as S. lydicus. 【Conclusion】Strain D2 has strong antagonistic effect to fusarium wilt of melon and worth to be developed as biological pesticides and fertilizers.

Key words： melon fusarium wilt； antagonistic bacteria； screening； identification； tropical zone

0 引言

【研究意義】甜瓜是我国广泛栽种的经济作物之一（张永平等，2017），据中国农业统计年鉴数据显示，2016年我国甜瓜种植面积超过48万ha，产量达1570万t；海南省2016年甜瓜种植面积为2823 ha，产量5.69万t。在甜瓜种植面积、产量和效益稳步上升的同时，甜瓜土传病害尤其是枯萎病日益严重，极大地限制了甜瓜产业的可持续发展。目前，防治甜瓜枯萎病的主要途径有化学药剂防治（周小林等，2007；杨长成等，2010；张静和胡立勇，2012；……