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journal1 ›› 2018, Vol. 34 ›› Issue (3): 440-448.DOI: 10.16409/j.cnki.2095-039x.2018.03.016

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Screening and Identification of Antagonistic Bacteria Bacillus pumilus against Cotton Fusarium Wilt and Biocontrol Research

LI Haiwei, HAN Wanli, WANG Mengyao, LUO Ming, HAN Jian, GU Aixing   

  1. Key Laboratory of the Pest Monitoring and Safety Control of Crops and Forests/College of Agronomy, Xinjiang Agricultural University, Urumqi 830052, China
  • Received:2018-01-31 Online:2018-06-08 Published:2018-06-14

Abstract: In order to obtain a better control effect of antagonistic Bacteria on cotton Fusarium wilt, from island cotton rhizosphere soil plant isolation of cotton wilt antagonistic bacteria, antibacterial effect research of antagonistic strains, provide a potential resource for its biocontrol bacteria. The antagonistic strains were screened from 120 strains of bacterial strains isolated from the soil by using the plate confrontation method, with the Fusarium oxysporum of the island cotton Fusarium wilt as the target bacteria. The inhibitory activity of antagonistic bacteria fermentation liquid was determined, and the best biocontrol strains were screened by buds and pot experiments. Meanwhile, the growth promoting effect and salt and alkali resistance of the strain to cotton were also determined. The classification status of the strains was identified based on the morphological characteristics, physiological, biochemical characteristics and 16S rDNA sequence analysis. A strain with strong antagonism to cotton blight was screened from 120 strains of bacteria, numbered KX-33. The germination analysis and pot experiment showed that KX-33 could obviously shorten the time of germination and promote the growth of cotton seedlings. The control effects of pathogenic bacteria DD64, DD89, DD11 and DD22 were 75.32%, 72.77%, 69.48% and 68.81% respectively, which were significantly higher than those of the control agents (P<0.05). The analysis of salt tolerance showed that the strain KX-33 had certain salt tolerance. The strain KX-33 microscopy was Gram-positive bacteria, rod-shaped, spore, 16S rDNA and sequence and homology with Bacillus pumilus (FJ763643.1) homology. The soil microorganism in the rhizosphere soil of the island cotton contains antagonistic bacteria against cotton wilt. It has been identified that KX-33 was Bacillus pumilus, and had strong potential of promoting growth and bacteriostasis. It has potential application in the biological control of Fusarium wilt of sea island cotton.

Key words: Fusarium wilt of cotton, Bacillus pumilus, biological control, identification

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