Abstract:
In order to screen for strains that have good antagonistic effects on tobacco
Fusarium root rot, bacteria that have good antagonistic effects were isolated and purified from the rhizosphere of healthy tobacco by the dilute coating plate method. Antagonistic bacteria were identified by morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis, and the growth promotion and disease control effects were determined. Two bacterial strains YX53 and YX 72 that have good antagonistic functions were selected. The plate inhibitory test showed that the inhibition efficiency of YX53 and YX72 were 83.66% and 73.54% against
F. solani, 57.57% and 55.89% against
F. oxysporum, respectively. The inhibition rate of YX53 and YX72 fermentation broth on pathogenic spore germination was 84.82%-100%, and the volatile organic compounds of the two antagonistic strains could inhibit the growth of pathogenic filaments or sporulation, also they had inhibitory effects on tobacco root disease pathogens such as
Phytophthora nicotiana,
Trichoderma basicola, etc. YX53 and YX72 were identified as
Bacillus cereus and
Bacillus subtilis, respectively. The two strains had significant growth promotion and disease inhibition effects. The radicle growth rate of the tobacco seeds treated with YX53 and YX72 reached 67.86% and 161.61%, respectively. And the root length, the maximum leaf area and fresh weight etc. of the treated seedlings were all increased. The disease prevention effects of YX53 and YX72 were more than 89.47% and 99.53% respectively.
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