烟草青枯病拮抗菌的筛选、鉴定和防病潜力评价

Screening,identification and biocontrol potential evaluation of antagonistic bacteria against tobacco bacteria wilt

为进一步丰富烟草青枯病的生防资源,通过平板稀释法,对贵州省黔南州4个烟区的健康烟株及根际土壤进行烟草内生细菌及根际细菌的分离纯化,共得到烟草内生细菌103株,根际细菌73株。利用抑菌圈法,筛选出抗青枯病菌的内生细菌LSN02和根际细菌LLGJ04,其抑菌圈直径分别为29.96和38.65 mm。进化分析结果表明,LSN02和LLGJ04均属于芽孢杆菌属且具有趋化性。盆栽试验中,LSN02和LLGJ04可有效增强烟株对青枯病的抗病能力。用中浓度(1×10~8cfu/mL)和高浓度(2×10~8cfu/mL)的LSN02菌株处理烟株时,烟草青枯病的病株率显著降低。

To explore biocontrol resources against tobacco bacteria wilt, a plate dilution method was used to isolate endophytic bacteria from healthy tobacco plants and rhizosphere bacteria from rhizosphere soils in four tobacco-growing areas of Qiannan in Guizhou Province. The results showed that a total of 103 endophytic bacteria and 73 rhizosphere bacteria were obtained. Endophytic bacteria LSN02 and rhizosphere bacteria LLGJ04 against tobacco bacteria wilt were screened by inhibition zone method, and their inhibition zone diameter were 29.96 and 38.65 mm, respectively. Phylogenetic analysis showed that LSN02 and LLGJ04 belonged to Bacillus sp. and existed chemotaxis. In pot experiments,LSN02 and LLGJ04 significantly enhanced the resistance of tobacco plants against bacterial wilt. The rate of tobacco plants infected by tobacco bacteria wilt significantly decreased under LSN02 treatment at a medium （1 × 10^8 cfu/mL） or high （2×10^8 cfu/mL） concentration.