烟草赤星病拮抗细菌的筛选、鉴定和抑菌机制研究

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Abstract： Tobacco brown spot，caused by Alternaria alternata ，is a prevalent disease during the mature stage of tobacco growth， significantly impacting both the yield and quality of tobacco leaves.To achieve sustainable and effective disease control，biocontrol strains of bacteria with high antifungal activity were identified from various tobacco-growing regions. Among the candidate strains，strain CX-2 demonstrated a pot control efficacy of 68.71% .Comprehensive morphological， physiological，biochemical，and molecular biological analyses confirmed that strain CX-2 is a Bacillus velezensis. In addition to its efficacy against A. alternata ， strain CX-2 exhibited strong inhibitory activity against multiple pathogenic fungi，including Fusarium pseudograminearum ， the causative agent of wheat root rot. Furthermore， strain CX-2 displayed robust cellulase activity， protease production，nitrogen fixation， phosphorus solubilization，and growth-promoting effects on tobacco. Optimization results of fermentation conditions revealed that strain CX-2 could maintain good fermentation performance under various conditions. The results showed that CX-2 strain has broad application potential in biological control.

Key words： Bacillus velezensis ； biological control; tobacco brown spot disease

烟草赤星病是一种由真菌引起的病害，其病原体为丝孢纲链格孢属的普通链格孢菌（Al-ternariaalternata）。（剩余11797字）