辣椒枯萎病拮抗木霉菌的筛选及鉴定

Screening and Identification of Antagonistic Trichoderma Against Fusarium Wilt in Capsicum

【目的】探明辣椒根际土壤中对尖孢镰刀菌(Fusarium oxysporum)有拮抗作用的微生物,筛选可抑制辣椒枯萎病的生防菌,为绿色防控辣椒连作导致的枯萎病提供有效的生防微生物资源。【方法】采用平板稀释法分离辣椒不同生长阶段根际土壤中的微生物,再通过平板对峙法筛选拮抗菌株并鉴定拮抗菌发酵液抑菌活性,结合形态学和分子生物学方法鉴定拮抗菌株种类。【结果】从辣椒根际土壤中共分离出真菌50株,其中5株木霉菌株对尖孢镰刀菌有拮抗作用,对峙培养抑菌率为60.47%~78.04%,LJ06020803菌株的抑菌率最高,为78.04%,其不含菌体的发酵液抑菌率为40.92%;根据LJ06020803菌株形态学特征和系统发育树鉴定其为哈茨木霉菌(Trichoderma harzianum)。【结论】菌株LJ06020803为哈茨木霉菌(Trichoderma harzianum),对辣椒枯萎病病原菌有很好的拮抗效果,可作为一种生防资源用于防治辣椒枯萎病。

【Objective】The antagonistic microbes against Fusarium oxysporum are isolated from rhizosphere soil of capsicum and the biocontrol bacteria against capsicum wilt are screened to provide the effective biocontrol microbe resources with greenly controlling capsicum wilt caused by the capsicum continuous cropping pattern.【Method】The microbes are isolated from rhizosphere soil of capsicum at different growth stages by using a plate dilution method, the antagonistic strains are screened by a plate confrontation method and the antibacterial activity of fermentation broth of the screened antagonistic bacteria and species of the screened antagonistic bacteria are determined and identified according by morphological and molecular biological methods.【Result】50 strains are isolated from rhizosphere soil of capsicum at different growth stages and the antibacterial rate of 5 isolated strains with an antagonism against F. oxysporum is 60.47%~78.04% in a plate confrontation culture. The antibacterial rate of strain LJ06020803 against F. oxysporum is up to 78.04%. The antibacterial rate of the fermentation broth of strain LJ06020803 against F. oxysporum reaches 40.92%. Strain LJ06020803 is identified as Trichoderma harzianum according to its morphological characteristics and phylogenetic tree.【Conclusion】Strain LJ06020803 with a good antagonistic effect against F. oxysporum causing capsicum wilt belongs to T. harzianum, which can be used as a biocontrol resource in further research of greenly controlling capsicum wilt.