一株拮抗水稻白叶枯病菌的淡紫灰链霉菌的筛选鉴定及其生防效果研究

 为发现绿色安全的水稻白叶枯病天然生物防治微生物,本研究从植物根际土壤中分离获得165株放线菌。利用共培养法和牛津杯法,筛选获得了5株拮抗水稻白叶枯病菌(Xanthomonas oryzae pv. oryzae, Xoo)的放线菌,其中拮抗能力最强的是Sl-10菌株,发酵液抑菌圈直径为62.1 mm ± 1.5 mm。根据形态特征、生理生化实验、16S rDNA序列和系统发育分析,鉴定Sl-10菌株为淡紫灰链霉菌(Streptomyces lavendulae)。Sl-10菌株发酵液对大豆斑点病菌(Pseudomonas syringae pv. glycinea)、烟草野火病菌(P. syringae pv. tabaci)、油菜黑腐病菌(X. campestris pv. campestris)、大豆斑疹病菌(X. axonopodis pv. glycines)、水稻条斑病菌(X. oryzae pv. oryzicola)、烟草青枯病菌(Ralstonia solanacearum)和番茄叶斑病菌(P. syringae pv. tomato)7种植物病原细菌均有拮抗作用。Sl-10菌株发酵液具有较好的耐光、耐酸碱和热稳定性。SDS-PAGE电泳结果显示,Sl-10菌株可抑制Xoo的蛋白质合成。4个品种水稻(甬优15、湘两优900、嘉丰2号和甬优1540)喷施Sl-10菌株发酵液,水稻白叶枯病的病斑抑制率达到82.27%~91.78%。研究结果显示,淡紫灰链霉菌Sl-10菌株具有较好的水稻白叶枯病生物防治潜能。

Screening,identification and biocontrol effect of a strain of Streptomyces lavendulae against Xanthomonas oryzae pv. oryzae

In order to find natural, environmental-friendly and safe biological control microorganisms against Rice Bacterial Blight (RBB), a total of 165 actinomycete strains were isolated from the rhizosphere soil of plants. Five strains of actinomycete with antagonistic resistance to Xanthomonas oryzae pv. oryzae (Xoo) were screened by coculture and Oxford cup methods. Among them, the Sl-10 strain exhibited the strongest antibacte-rial activity (inhibition zone diameter 62.1 mm ± 1.5 mm). According to morphological characteristics, physiological and biochemical experiments as well as 16S rDNA sequencing and phylogenetic analysis, the Sl-10 strain was identified as S. lavendulae. The S. lavendulae Sl-10 fermentation broth showed biological activities against 7 kinds of plant pathogenic bacteria including P. syringae pv. glycinea, P. syringae pv. tabaci, X. campestris pv. campestris, X. axonopodis pv. glycines, X. oryzae pv. oryzicola, R. solanacearum and P. syringae pv. tomato. The S. lavendulae Sl-10 fermentation broth possessed light resistance, acid-base resistance and heat stability. The result of SDS-PAGE revealed that the S. lavendulae Sl-10 may exert an antagonistic effect by inhibiting Xoo protein synthesis. Four rice varieties (Yongyou 15, Xiangliangyou 900, Jiafeng 2 and Yongyou 1540) which have been sprayed with the fermentation broth of S. lavendulae Sl-10 could effectively prevent the occurrence of RBB, and the leaf disease spot inhibition rate of 4 rice varieties reached 82.27%-91.78%. The above results show that S. lavendulae Sl-10 has broad application potential for the biological control of RBB.