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为探明河北昌黎野生大豆内生细菌的多样性,寻找新的具有杀线虫活性的微生物资源,采用平板稀释法从野生大豆根、茎、叶等组织中分离内生细菌,结合形态特征以及16S rDNA基因序列进行比对分析,并对大豆孢囊线虫Heterodera glycines进行杀线虫活性比较。从野生大豆分离获得内生细菌180株,分属于7大类群:变形菌门α亚群、变形菌门β亚群、变形菌门γ亚群、厚壁菌门、放线菌门、酸杆菌门和疣微菌门,其中变形菌门α亚群和厚壁菌门为优势类群,分别占分离细菌总株数的48.9%和18.9%,野生大豆组织内生细菌Shannon-Wiener多样性指数为2.11~2.91。内生细菌Bacillus subtilis WSR93和B.megaterium WSR22菌株能明显地抑制大豆孢囊线虫卵的孵化,相对抑制率分别为97.9%和98.2%,对2龄幼虫也有较强的毒杀作用,校正死亡率分别为88.9%和90.9%。研究表明,野生大豆组织中内生细菌具丰富的多样性,其胞外分泌物中存在天然杀线活性物质。
In order to find out the diversity of endophytic bacteria in wild soybean in Changli, Hebei Province, and to search for new microbial resources with nematicidal activity, endophytic bacteria were isolated from the roots, stems and leaves of wild soybean by plate dilution method. The morphological characteristics and 16S rDNA gene sequences were compared and the nematicidal activity of Heterodera glycines was compared. 180 strains of endophytic bacteria were isolated from wild soybean, belonging to 7 groups: Proteus alpha subgroup, Proteus beta subgroup, Proteus gamma subgroup, Firmicutes, Actinobacteria, The dominant species were Proteobacteria α-subpopulations and Firmicutes, accounting for 48.9% and 18.9% of the total isolates respectively. The Shannon-Wiener diversity index of endophytic bacteria in wild soybean was 2.11 ~ 2.91. The endophytic bacteria Bacillus subtilis WSR93 and B.megaterium WSR22 could significantly inhibit the hatching of soybean cyst nematode eggs with the relative inhibition rates of 97.9% and 98.2%, respectively. They also had strong toxic effects on the 2nd instar larvae and corrected the mortality The rates were 88.9% and 90.9% respectively. Studies have shown that endophytic bacteria in wild soybean tissue is rich in diversity, and its extracellular secretions in the presence of natural anti-line active substances.