郑少兵　孙正祥　徐梦亚

摘要 本文旨在筛选对水稻纹枯病有生防作用的菌株，并初步探索其生防作用机理。收集水稻、甘蓝、黄瓜等不同植物根际土壤，采用稀释分离和对峙培养法筛选对水稻纹枯病菌Rhizoctonia solani Kühn有抑菌作用的菌株;通过离体接种防效、盆栽防效、抑菌谱、对水稻纹枯病菌菌核萌发及形成的抑制作用等方面评价其生防潜力，并对生防菌株进行鉴定。结果表明，从采集的37份根际土壤中共分离获得细菌297株，其中4株对纹枯病菌具有较好的拮抗作用，菌株YU-1对水稻纹枯病菌菌丝生长的抑制率达89.8%;对西瓜枯萎病菌、草莓灰霉病菌、番茄早疫病菌、油菜菌核病菌、小麦赤霉病菌菌丝生长的抑制率均在85%以上;对水稻纹枯病的离体和盆栽防效分别为73.1%和66.3%;对水稻纹枯病菌菌核萌发的抑菌率在92%以上;经生理生化和分子鉴定为解淀粉芽胞杆菌Bacillus amyloliquefaciens。由此可看出，菌株YU-1对水稻纹枯病的防治具有较强的应用价值，具有进一步开发成生物农药的潜力。

关键词 水稻纹枯病; 根际; 生防作用; 解淀粉芽胞杆菌

中图分类号： S 476.1

文献标识码： A

DOI： 10.16688/j.zwbh.2019141

Control effect of Bacillus amyloliquefaciens YU-1 on rice sheath blight

ZHENG Shaobing1，2， SUN Zhengxiang2*， XU Mengya2，3

（1. Guangxi Key Laboratory of Biology for Crop Disease and Insect Pests， Nanning 530007， China;

2. College of Agriculture， Yangtze University， Jingzhou 434025， China; 3. Laboratory of Microbial

Resources Collection and Preservation， Ministry of Agriculture and Rural Affairs， Beijing 100081， China）

Abstract

This study was aimed to discover bacterial strain with biocontrol activity against rice sheath blight （RSB） and preliminarily explore its biocontrol mechanism. The bacterial strains isolated from rhizosphere of rice， cabbage， cucumber et al.， with strong antagonistic effects on Rhizoctonia solani Kühn（RS）， were screened by confrontation culture. The biocontrol potential was evaluated by vitro inoculation， pot experiments， antagonistic spectrum， germination inhibition and sclerotium formation tests. The results showed that the inhibition activity of stain YU-1 on RS mycelia growth was 89.8%， and that on mycelia growth of watermelon wilt， strawberry grey mould， tomato early blight， rapeseed germ and wheat red mould was more than 85%. Control efficacies on RSB were 73.1% and 66.3% in vitro and pot tests， respectively. The germination inhibition on RS sclerotium was more than 92%. Based on physiological and biochemical characteristics and molecular naturalization identification， the strain YU-1 was identified as Bacillus amyloliquefaciens. These results showed that strain YU-1 had strong application value to control RSB and significant potential to be developed into biopesticide.

Key words

rice sheath blight; rhizosphere; biocontrol effect; Bacillus amyloliquefaciens

水稻是我國的主要粮食作物之一，由立枯丝核菌Rhizoctonia solani Kühn侵染引起的纹枯病是水稻的三大病害之一[1]。病原菌形成的菌核抗性强，在土壤里存活时间长，发病时可以借助植物叶片横向传播，具有土传和叶传特点[2]。该病害一般可造成减产10%～30%，较重时减产达50%[3]。目前生产中尚无高抗品种，主要采用己唑醇、三唑酮、苯醚丙环唑、噻呋酰胺等化学药剂防治，随着生态环保及抗药性问题逐渐受到关注，化学防治面临严峻的挑战[4]。……