[Objective]To isolate plant endophytes with broad-spectrum antibacterial activity from mangrove plant tissues.[Method]Pseudo-monas aeruginosa,Pasteurella multocida,Enterobacter aerogenes and Enterococcus faecalis were selected as indicator bacteria.M10 and P3 solid medias and agar-well diffusion were used to isolate and screen endophytes with antibacterial activity from root,stem and leaf tissues of mangrove plants.Extracted DNA were used as template for PCR amplification of the 16S rDNA gene and sequenced to construct a phylogenetic tree by neighbor-joining method.[Result]A total of 857 culturable bacteria were isolated from mangrove plant tissues and 145 strains had inhibitory ac-tivity,accounting for 16.6％of the isolates.The strain 32-5,isolated from mangrove plant leaf tissue using M10 solid medium,had the strongest inhibitory activity against Pseudomonas aeruginosa and Enterobacter aerogenes,with an inhibition circle diameter of 38 mm and 42 mm,respec-tively.Strain 12-4 isolated from mangrove plant stem tissue using P3 solid medium showed the strongest inhibitory activity against Enterococcus faecalis with an inhibition circle diameter of 56 mm.Strains 13-2 isolated from mangrove plant stem tissues using M10 medium showed the stron-gest inhibitory activity against Pasteurella multocida with an inhibition circle diameter of 64 mm.Bacteria with antibacterial activity were classi-fied into 10 genus,of which Bacillus was the dominant genus.[Conclusion]This experiment initially revealed the antibacterial activity and di-versity of endophytic bacteria in mangrove plant roots,stems and leaf tissues,providing a theoretical basis for the development and application of new antibacterial drugs.
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