Biological control of root rots on alfalfa with Streptomyces

In the current study, strain D1 was screened from saline-alkali soil of grassland by the method of plate confrontation. The inhibition rates against Fusarium equiseti BS1 , Fusarium oxysporum BF28 , Fusarium oxysporum BF19 and Fusarium solami BF36-2 were 70.81% , 76.00% , 67.80% and 65.70% respectively. Strain D1 was identified as Streptomyces ciscaucasicus by observation of colony morphology, physiological and biochemical characteristics and sequence analysis of 16S rRNA gene. The results of antimicrobial spectrum showed that the strain had antagonistic effect against 9 kinds of plant pathogenic fungi. The control effect of the strain on alfalfa root rot was 52.8% and it could promote rooting. The results showed that the strain D1 had potential as a biological agent