Screening and Identification of Biocontrol Bacteria for Cotton Verticillium Wilt and Effect of Rhizobium DG3-1 on Cotton Growth
The aim of this study was to explore the germplasm resources of endophytic bacteria in south-ern Xinjiang cotton for the prevention and control of cotton Verticillium wilt,and also explore the impact of rhi-zobia on cotton growth.Endophytic bacteria were isolated from different tissues of cotton using conventional tis-sue separation method.Antagonistic endophytic bacteria against Verticillium dahliae were screened by plate confrontation method,and then molecular identification was performed.The effects of rhizobia on cotton growth were studied by pot experiments.The results showed that there were certain differences in the number of endo-phytic bacteria in different tissues of cotton and that in roots was the most,followed by leaves and stems.A-mong the 31 strains of isolated endophytic bacteria,11 showed antagonistic activity against cotton V.dahliae with inhibition rates of 35.99%～68.28%.After identification,9 strains of Bacillus and 2 strains of Rhizobium were identified,among which Rhizobium DG3-1 had a inhibition rate of(56.63±1.82)%against cotton V.dahliae.The results of the pot experiment showed that compared to the control,the aboveground fresh weight,aboveground dry weight,underground fresh weight,underground dry weight and chlorophyll content in cotton plants treated with strain DG3-1 increased by 2.12,2.09,1.05,0.75 and 1.75 times,respectively.Strain DG3-1 had good antibacterial effect against cotton V.dahliae and certain promoting effect on cotton growth,which was a potential strain for cotton V.dahliae prevention and control,and could provide strain resources for the development of microbial agents.
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