Screening, Growth Promotion, and Disease Control of Antagonistic and Endophytic Bacteria in Tobacco

To obtain stable bacterial strains with good growth promotion of tobacco and black shrank disease control effect, 478 endophytic bacterial strains were isolated from tobacco leaves and stems. Among them 65 of strains (accounting for 13.60%) could inhibit Phytophthora parasitica var. nicotianae by the traditional methodology. Especially, the four strains, YN201408, YN201442, YN201448 and YN201458 inhibited 63.85%, 60.82%, 64.72% and 76.07% of mycelia growth of the pathogen and controlled 68.24%, 65.47%, 69.12 and 41.40% of disease severity by soaking the seedling root in 1.0×10⁷cfu/mL of the bacterial suspension for 30 min and drenching once after transplanting in the pot experiment in the greenhouse, respectively. YN201448 could promote seed germination and growth of tobacco, showing 10.95%, 29.31% and 67.24% higher than water control in germination rate, seedling height during 5-6 leaf stage and fresh weight on the ground. YN201408, YN201442 and YN201448 were classified into Bacillus amyloliquefaciens, and YN201458 into Pseudomonas aeruginosa based on their morphology, physiological and biochemical traits and 16S rDNA sequences. YN201448 showed good potential for application based on its growth promotion and disease control effect.