Abstract:
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.
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