王瑞昊 邓业成 陈广桂 张泽 张燕玲 邓志勇 蓝福生 郭丽霞 张川梅 梁保明 骆海玉 张明良

摘要：【目的】從罗汉果根际土壤中筛选分离出对白绢病（southern blight）与根腐病（root rot）有抑制作用的拮抗细菌，为罗汉果土传病害生物防治提供合适菌株。【方法】采用稀释涂布法和划线法从罗汉果果园土壤中分离纯化出拮抗细菌114株。随后对分离出的拮抗细菌采用平板对峙法进行抑菌活性筛选。通过16S rDNA序列分析，结合菌落形态特征，生理生化特征对菌株进行鉴定。【结果】22株细菌对至少1种罗汉果土传病原真菌表现出小同程度的抑制作用。其中5株细菌即TYX-2、TYX-3、TYX-4、TYX-7和TYX-8对根腐病与白绢病抑制作用最为明显，对罗汉果根腐病菌的抑制率分别为67.53%、57.50%、64.17%、60.00%和66.67%。对罗汉果白绢病菌的抑制率分别为83.03%、87.58%、53.3 1%、82.27%和86.67%。经过形态学、生理生化特征以及16S rDNA系统发育树的分析，确定TYX-2、TYX-7和TYX-8为贝莱斯芽孢杆菌（Bacillus velezia），TYX-3为枯草芽孢杆菌（Bacillus subtilis），TYX-4为解淀粉芽孢杆菌（Bacillus amyloliquefaciens）。贝莱斯芽孢杆菌TYX-2、枯草：芽孢杆菌TYX-3和解淀粉芽孢杆菌TYX-4发酵液对2种罗汉果病原真菌电有较好的抑制作用，对罗汉果根腐病菌的抑菌率分别为47.83%、48.67%和45.83%，对罗汉果白绢病菌的抑菌率分别为5 2.00%、50.42%和55.83%。【结论】分离鉴定出的TYX-2、TYX-3和TYX-4分别为贝莱斯芽孢杆菌、枯草芽孢杆菌和解淀粉芽孢杆菌，具有较高的生防应用价值，为进一步研制复合生防菌剂，防治罗汉果土传病害奠定理论基础。

关键词：罗汉果;根腐病菌;白绢病菌;分离鉴定;拮抗细菌

中图分类号：S 435

文献标志码：A

文章编号：1008-03 84（ 2021） 080927-09

Antagonistic Bacteria against Soil-borne Diseases on Siraitia grosvenornWANGRuihao 1. DENGYecheng 1*， CHENGuanggui 1， ZHANGZe 1. ZHANGYanling 2， DENGZhiyong 1， LANFusheng 2，GUO Lixia 2. ZHANG Chuanmei 2. LIANGBaoming 2， LUO Haiyu 1， ZHANGMingliang 2（I. College of Life Sciences， Guangxi Normal University. Guilin， Guangxi 54 1004， China;2. Guilin GFS Monk Fruit Crop， Guilin， Guangxi 541006. China ）

Abstract： 【Object】Microbes with potential of being used as biological control agents against the southern blight and rootrot diseases on Siraitia grosvenorii were screened and identified from the thizosphere soil in the field. 【Method】A total of114 strains of presumably antagonistic microorganisms were isolated from the soil at a S. grosvenorii orchard by means ofdilution coating and streaking. The isolates were screened for their antibacterial activity using the plate confrontation method.and subsequently， identified by 16S rDNA sequence analysis along with observations on the colony morphology and microbialphysiochemical characteristics. 【Result】Twenty-two isolated strains displayed varying degrees of inhibition effect on one orboth root rot and southern blight pathogens. They included the bacteria under the coded names of TYX-2. TYX-3. TYX-4.TYX-7. and TYX-8 with inhibition rates on the root rot of 67. 53 %， 57.50%. 64.17%， 60.00%. and 66.67%， respectively， and onthe southern blight with the rates of 83.03%. 87.58%. 53.3 1%. 82.27%， and 86.67%， respectively. TYX-2， TYX-7. and TYX-8were identified to be Bacillus velezia. TYX-3 B. subtilis. and TYX-4 B. amyloliquefaciens. The fermentation broths of TYX-2.TYX-3， and TYX-4 also showed significant inhibition rates on the root rot pathogen at 47.83%. 48.67%. and 45.83%.respectively， and 52.00%. 50.42%. and 55.83% on the southem blight. 【Conclusion】 The isolated B. velez， B. subtilis'. and B.amyloliquefaciens strains displayed significant inhibitory effects on the root rot and southern blight of S. grosvenorii. Theycould be studied further for a potential application as agents for biocontrol on the diseases.

Key words： Siraitia grosvenorii; root rot; southern blight; isolation and identification： biocontrol bacteria

0 引言

【研究意義】罗汉果Siraitia grosvenorii （Swingle）C.Jeffrey为葫芦科Cucurbitaceae罗汉果属Siraitia多年生草质藤本宿根植物，又名汉果、长寿果、神仙果，是我国特有甜料及珍贵药用植物。……