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【目的】从河南大豆根瘤的内生细菌资源中筛选对稻瘟病菌有拮抗作用的菌株,初步探讨其抑菌效果,为进一步研究其抑菌机理提供菌种资源。【方法】以稻瘟病菌为供试病原菌,采用对峙法进行拮抗性菌株筛选,显微观察法研究受抑制病原菌菌丝变化,对筛选拮抗性菌株进行细胞形态学及生理生化特性试验、16S rRNA基因测序和系统发育分析及接种防效试验。【结果】经复筛有17株内生菌拮抗效果较明显,最高抑制率为62.16%;受抑制病原菌丝呈现弯曲打结、断裂、原生质浓缩等畸形状态。拮抗性筛选过程中内生菌快速生长形成生物薄膜,包埋菌丝并使其断裂。拮抗菌株分布在7属9种,稻瘟病拮抗性大豆根瘤内生菌呈现种属多样性。防效试验表明内生菌处理组稻苗发病率和病情指数均显著降低,防治效果最高达74.19%。【结论】大豆根瘤内生拮抗性菌株具有种属多样性,拮抗性菌株处理组稻苗发病率和病情指数均显著降低,防治效果显著,为进一步研究其抑菌机理提供菌种资源。
【Objective】 The objective of this study was to screen out strains that antagonize Magnaporthe grisea from endophytic bacterial resources of soybean nodules in Henan Province, and to explore the antibacterial activity of the strains in order to further study their antibacterial mechanism to provide fungal resources. 【Method】 The antagonistic strains were screened by the confrontation method with Magnaporthe grisea as tested pathogens. The microscopic observation method was used to study the morphological and physiological and biochemical characteristics of antagonistic strains. The 16S rRNA Gene sequencing and phylogenetic analysis and vaccination control. 【Result】 The results showed that 17 strains of endophytic bacteria were re-screened with obvious antagonistic effect, the highest inhibition rate was 62.16%. The degenerative state of curly knot, rupture and protoplasm concentration of pathogenic mycelium showed inhibition. During the antagonistic screening process, the endophytes grow rapidly to form biofilms, which embed and break the mycelium. Antagonistic strains were distributed in 9 genera of 7 genera, and endophytic bacteria of antagonistic soybean root nodule in rice blast showed species diversity. The anti-efficacy test showed that the endophyte-treated rice seedlings incidence and disease index were significantly reduced, the control effect of up to 74.19%. 【Conclusion】 Endophytic antagonistic strains of soybean root nodules have species diversity. The incidence and disease index of rice seedlings treated with antagonistic strains are significantly decreased, and the control effect is remarkable. It provides species resources for further study of its antibacterial mechanism.