Screening And Control Effect Of Sunflower White Mold And Verticillium Wilt Biocontrol Strains

In order to screen out biocontrol strains with good control effect against Sclerotinia sclerotiorum and Verticillium wilt of sunflower,Three strains were screened from 177strains(33 endophytic strains of sunflower,144 strains of laboratory strains)with strong control effects on sunflower sclerotinia sclerotiorum and Verticillium wilt,which were numbered TZ-1,GF-46 and KB3.The species and genus of the effective antagonistic strains were determined by morphological,physiological and biochemical characteristics experiments and 16 S r RNA gene sequencing.The results showed that THE strain TZ-1was Bacillus megaterium,the strain GF-46 was Bacillus velezensis,and the strain KB3 was Bacillus subtilis.Under the pot condition,the control effects of TZ-1,GF-46 and KB3 against sunflower Sclerotinia sclerotiorum were 77.85%,80.89% and 79.47%,and against Verticillium wilt were 54.46%,69.31% and 67.47%.The compound biocontrol solution of Tz-1,GF-46 and KB3 was prepared according to the ratio of 1:1:1,which was used for the biological control of Sclerotinia sclerotiorum and Verticillium wilt of sunflower seedlings.The control effect of the compound bacteria on sunflower Sclerotinia sclerotiorum was 82.72% and that on sunflower Verticillium wilt was 72.28%under greenhouse conditions.The control effect on Verticillium wilt of sunflower was51.03% when the compound bacteria were applied to field.Prediction of secondary metabolite gene cluster of strain KB3 by whole-genome sequencing experiment The results showed that Rhizocticin A,Surfactin,Butirosin A / B,Macrolactin H,Bacillaene,Fengycin,Difficidin,Bacillibactin,Subtilin,Subtilosin A,Bacilysin and other antibiotics inhibit plant pathogenic fungi.The three strains screened in this study had good control effect on Verticillium wilt and Sclerotinia sclerotiorum of sunflower and had certain application value.