Screening and identification of actinomycetes for biocontrol of kiwifruit bacterial canker
179 actinomycete strains isolated from Barkol and Dabancheng salt lakes in Xinjiang were screened for an-tagonistic effects against Pseudomonas syringae pv.actinidiae.Eight actinomycete strains with antagonistic effects were identified,among which ZBW8-1,E14-3,and ZB5-6 showed the most significant antimicrobial activity,with the diame-ters of inhibition zones of 27.5 mm,23.6 mm,and 26.2 mm,respectively.Colony morphology observation,16s rRNA amplification and sequencing,and phylogenetic analysis based on 16s rRNA sequences were conducted on these three strains of actinomycetes.PCR identification of antibiotic synthesis-related genes was performed on these strains.The re-sults show that the actinomycetes ZBW8-1,E14-3,and ZB5-6 have the highest 16s rRNA sequence homology with Gly-comyces fuscus TRM 49117(99.86％),Promicromonospora vindobonensis V45T(99.1％),and Nocardiopsis terrae YIM 90022T(99.86％),respectively.In terms of evolutionary relationships,these three strains are also clustered on the same branch as the aforementioned strains.ZBW8-1,E14-3,and ZB5-6 strains all carry the NRPS gene,among which ZBW8-1 and ZB5-6 strains also contain the PKS-Ⅱ gene,and ZBW8-1 strain also contains the PKS-Ⅰ gene.Analyzing the evolutionary status of these active actinomycetes and identifying their functional genes related to antibiotic synthesis will lay a theoretical foundation for studying the bioactive secondary metabolites in these strains.
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