拮抗烟草疫霉菌的趋化性内生细菌筛选及其对烟草黑胫病的防效

以烟草疫霉菌为靶标，从3 000株烟草叶片内生细菌中筛选出拮抗菌483株，抑菌率在9.55%～55.96%之间.从这483株拮抗菌中筛选出11株趋化性内生生防细菌，鉴定为Brevibacillus brevis、Br.parabrevis、Br. formosus、Br. reuszeri、Pseudomonas aeruginosa、Ps. tremae、Ps. umsongensis和Erwinia rhapontici.温室试验结果显示，Br. brevis Hs8-19,Br. brevis Hs8-13和Ps. tremae Ht3-25单独使用时，对烟草黑胫病的防效分别为62.43%、57.67%和53.43%.当在菌液中添加终浓度为40μmol/L尼古丁时，Br. brevis Hs8-19,Br. brevis Hs8-13和Ps. tremae Ht3-25对烟草黑胫病的防效分别增加了6.11%、4.79%和4.72%.

Screening of chemotactic endophytic bacteria against Phytophthora nicotianae and their control effects towards tobacco black shank

A total of 3000 endophytic bacteria were isolated from the healthy leaves of tobacco. Of them, 483 antagonistic strains were screened out with Phytophthora nicotianae as the target, and the inhibition rate ranged from 9.55% to 55.96%. From these 483 antagonistic strains, 11 chemotactic endophytic bacteria were screened out and were identified as Brevibacillus brevis, Br. formosus, Br. reuszeri, Pseudomonas aeruginosa, Ps. tremae, Ps. umsongensis and Erwinia rhapontici. Under greenhouse condition, endophytic bacteria Br. brevis HS8-19, Br. brevis HS8-13 and Ps. tremae HT3-25 showed their control efficiencies towards tobacco black shank with values of 62.43%, 57.67%, and 53.43%, respectively, when used alone. When nicotine was added to the bacterial solution with the concentration of 40 μmol/L, the control efficiencies of the three strains were increased by 6.11%, 4.79% and 4.72%, respectively. Results of our study indicate that the combination of chemotactic-biocontrol bacteria and chemotactic substances has important potential in the control of tobacco black shank.