刘莎莎，程园园，张丹，王晓丹，刘佳莉，郭长虹

(哈尔滨师范大学生命科学与技术学院，分子细胞遗传与遗传育种黑龙江省重点实验室，黑龙江 哈尔滨 150025)

两株紫花苜蓿根际芽孢杆菌的筛选及生防效果研究

刘莎莎**，程园园**，张丹，王晓丹，刘佳莉，郭长虹*

(哈尔滨师范大学生命科学与技术学院，分子细胞遗传与遗传育种黑龙江省重点实验室，黑龙江 哈尔滨 150025)

摘要：从紫花苜蓿根际土中分离出2株芽孢杆菌(Bacillus spp.)菌株CYY-6和CYY-42，并评价了其对尖孢镰刀菌(Fusarium oxysporum)的抑制作用，及其对由尖孢镰刀菌引起的苜蓿根腐病的防治效果。经过形态观察、16S rDNA序列分析和生理生化鉴定，确定菌株CYY-6为地衣芽孢杆菌(Bacillus licheniformis)，CYY-42为短短芽孢杆菌(Brevibacillus brevis)。同时检测发现这2株芽孢杆菌均能不同程度地合成嗜铁素。在平板对峙实验中，2株菌株均能对尖孢镰刀菌产生拮抗作用，并产生抑菌带，抑菌率分别为49.3%和56.3%。且其发酵液可以致使尖孢镰刀菌菌丝及孢子生长异常，出现菌丝扭曲、断裂、破碎，孢子数量明显减少等现象。在盆栽实验中，2株菌株对由尖孢镰刀菌引起的紫花苜蓿根腐病的相对防效分别为57.55%和64.03%，在紫花苜蓿根腐病防治方面具有较好的应用潜力。

关键词：芽孢杆菌；紫花苜蓿；生物防治；尖孢镰刀菌；根腐病

Isolation, identification, and biocontrol effects ofBacillusspp. from the rhizosphere of alfalfa

LIU Sha-Sha**, CHENG Yuan-Yuan**, ZHANG Dan, WANG Xiao-Dan, LIU Jia-Li, GUO Chang-Hong*

KeyLaboratoryofMolecularCytogeneticsandGeneticBreedingofHeilongjiangProvince,CollegeofLifeScienceandTechnology,HarbinNormalUniversity,Harbin150025,China

Abstract:The aims of this study were to identify two Bacillus spp., CYY-6 and CYY-42, isolated from the rhizosphere of alfalfa, and to evaluate their ability to inhibit Fusarium oxysporum, the causal pathogen of alfalfa root rot. Based on physiological, biochemical, morphological, and 16S rDNA sequencing analyses, strain CYY-6 was identified as Bacillus licheniformis and CYY-42 as Brevibacillus brevis. Both strains were able to synthesize siderophores, although at different levels. In a dual culture assay, both strains inhibited the growth of F. oxysporum. Based on the inhibition zones, the inhibitory rates of CYY-6 and CYY-42 against F. oxysporum were 49.3% and 56.3%, respectively. The fermentation broth of each strain resulted in deformed growth of the mycelia and spores of F. oxysporum. The mycelia were twisted, broken, or fragmented, and the number of spores was significantly decreased. Strains CYY-6 and CYY-42 showed 57.55% and 64.03% inhibition of alfalfa root rot in pot experiments, indicating that both strains have potential applications in controlling alfalfa root rot.

Key words:Bacillus spp.; alfalfa (Medicago sativa); biocontrol; Fusarium oxysporum; root rot

紫花苜蓿(Medicagosativa)是世界上栽培最广的优质多年生豆科牧草，具有产草量高、再生性强、利用年限长、适口性强、营养丰富等优点。至今，紫花苜蓿在我国的种植历史已超过两千年，是我国种植面积最大的牧草[1-3]。……