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从烤烟品种K326的不同生长时期分离内生细菌1000株,以烟草黑胫病菌(Phytophthora parasitica var.nicotianae)为靶标,共筛选出168株拮抗菌,这些内生细菌对黑胫病菌的抑菌率在12.54%～50.14%之间。苗期和团棵期的内生菌含量较高,但在开花和成熟期时降低了一个数量级,而拮抗菌数量呈上升趋势。对168株拮抗菌的16SrRNA基因序列进行RFLP分析,共产生10种带型。根据RFLP带型选取39株进行16S rRNA基因序列测定和系统发育分析。结果表明,这168株生防内生细菌归于2大类群:Firmicutes和Actinobacteria。Firmicutes类群中的芽孢杆菌属(Bacillus)是优势属,共6种RFLP带型,150个菌株,包括Bacillus amyloliquefaciens subsp.plantarum,Bacillus tequilensis,Bacillus methylotrophicus,Bacillus cereus,Bacillus thuringiensis和Bacillus aryabhattai。Bacillus amyloliquefaciens subsp.plantarum和Bacillus methylotrophicus的出现频率最高,共126株,占该属总菌株数的78.75%。其余18个菌株分属于4个种:即Brevibacillus formosus,Brevibacillus parabrevis,Pseudomonas umsongensis和Pseudomonas aeruginosa。
1000 strains of endophytic bacteria were isolated from different growth stages of flue-cured tobacco cultivar K326. A total of 168 antagonistic bacteria were screened out against Phytophthora parasitica var. Nicotianae. The antibacterial activity of these endophytic bacteria against Phytophthora parasitica In the range of 12.54% ~ 50.14%. Endophyte and seedling stage endophyte content higher, but in flowering and maturity decreased by an order of magnitude, while the number of antagonistic bacteria is on the rise. The 16SrRNA gene sequences of 168 antagonistic bacteria were analyzed by RFLP, and 10 bands were produced. According to RFLP banding, 39 strains were selected for 16S rRNA gene sequence analysis and phylogenetic analysis. The results showed that the 168 biocontrol endophytic bacteria belong to two groups: Firmicutes and Actinobacteria. Bacillus in the Firmicutes taxa are the dominant genus, and there are 6 RFLP bands and 150 strains including Bacillus amyloliquefaciens subsp. Plantarum, Bacillus tequilensis, Bacillus methylotrophicus, Bacillus cereus, Bacillus thuringiensis and Bacillus aryabhattai. Bacillus amyloliquefaciens subsp.plantarum and Bacillus methylotrophicus appeared most frequently, accounting for a total of 126 strains, accounting for 78.75% of the total number of the genus. The remaining 18 strains belong to 4 species: Brevibacillus formosus, Brevibacillus parabrevis, Pseudomonas umsongensis and Pseudomonas aeruginosa.