Abstract:

By tissue isolation method of the local isolate of Dark septate endophytes（DSE）strains from healthy roots of Lycium barbarum‘Ningqi 5’in order to further provide potential resources bacteria for the biological control of Fusarium oxysporum. The confrontation method,mycelium growth rate method,spore germination method,and pot experiments were conducted to evaluate the antibacterial activities of DSE against F. oxysporum in L. barbarum. The results showed that eight DSE strains could effectively colonize the roots of L. barbarum and form a typical DSE structure. In the meanwhile,all eight DES strains showed a significant inhibitory effect against F. oxysporum,the Cladosporium cladosporioides strain S12 had the highest inhibition rate of 81.47% on the mycelial growth of F. oxysporum;The fermentation filtrate and volatile substances of the eight DSE strains exhibited certain inhibitory effects on the growth of F. oxysporum,and the fermentation filtrate of strain S12 with a concentration of 10% showed the highest inhibitory effect on F. oxysporum mycelial growth,reached up to 78.43%;The fermentation filtrate of the Alternaria alternata strain M1 with a concentration of 50% showed the highest inhibition of conidial germination with 91.48%. Meanwhile,the volatile material produced by strain M1 exhibited the highest inhibition of mycelial growth with 94.10%. In the greenhouse pot experiment,inoculation with strains M1 and S12 provided a good biological control effect,with efficacy up to 89.54% and 83.17%,respectively,better than a treatment of 500× dilution 50% carbendazim wettable powder. These results demonstrate that DSE strains M1 and S12 can effectively control the root rot of disease L. barbarum,while having good potential for biological control and application.

Key words: Lycium barbarum, dark septate endophytes, root rot disease of Lycium barbarum, inhibitory effect, biocontrol control