拮抗假禾谷镰孢菌的LZ-7菌株筛选、鉴定及其生防潜能OA北大核心CSTPCD

[Objective]The objective of this study is to isolate and screen out the bacterial strain with inhibitory effect on Fusarium pseudograminearum from soil,and identify the strain species and analyze its biocontrol potential.[Method]The rhizosphere soil of trees in the natural habitat of Linzhi was dis-solved with sterile water and the supernatant was taken to isolate the bacteria strains by dilution-plating method.After purification,the strains that against F.pseudograminearum mycelial growth were screened by plate confrontation method.The isolated strain was identified based on its morphology,physiological and biochemical characteristics,and 16S rDNA sequence similarity.The inhibitory effect of the candidate strain on Fusarium crown rot(FCR)in wheat seedling stage was examined by a pot-culture experiment.The bacteriostatic spectrum of candidate strain that against other fungal pathogens were determined by plate confrontation method.[Result]In this study,an bacterium strain LZ-7 was isolated and screened that had strong antagonistic effect against F.pseudograminearum,with the inhibi-tion rate of 52.3％.The strain LZ-7 can produce amylase,cellulase,urease and gelatinase,and use a variety of carbon sources.Finally,the LZ-7 strain was identified as Streptomyces rochei because its 16S rDNA sequence and Streptomyces rochei clustered in the same branch.Under greenhouse conditions,the LZ-7 strain treatment showed a relative FCR control rate of 58.4％.Furthermore,we also found that the LZ-7 strain showed antagonistic effect on some other fungal pathogens,such as Fusarium gra-minearum and Bipolaris sorokiniana.[Conclusion]The S.rochei LZ-7 strain was screened from the soil of the Qinghai-Xizang Plateau,which inhibited the growth of F.pseudograminearum and the disease of FCR.Thus,LZ-7 strain has the potential to be applied in the prevention and control of FCR.