Diversity of culturable endophytic bacteria in Acanthus ebractea-tus of Guangxi and their growth-promoting,biocontrol effect and enzyme production activity
[Objective]The aim was to analyze the diversity of culturable bacteria of Acanthus ebracteatus in Guangxi and their growth-promoting,biocontrol effect and enzyme production activity,so as to provide reference for the recovery of A.ebracteatus ilicifolius population and the screening of available strain resources.[Method]The culturable bacteria in the roots,stems,leaves and rhizosphere soil were isolated and purified by dilution coating method.The 16S rRNA se-quence of the strain was amplified by PCR,and the sequencing results were compared by EzBioCloud to determine the taxonomic status of the strain.The growth-promoting[phosphate solubilization,nitrogen fixation,indoleacetic acid(IAA)production and siderophore secretion],disease prevention(banana fusarium wilt)and enzyme production(protea-se,amylase and cellulase)activities of the strains were analyzed by functional medium.[Result]A total of 159 strains of bacteria were screened from the roots,stems,leaves and rhizosphere soil of A.ebracteatus.According to the colony mor-phology and the 16S rRNA sequencing results,65 strains were excluded after duplication,belonging to 8 orders,7 fami-lies and 14 genera.Among them,Bacillus was the dominant genus,accounting for 64.62% of the isolated strains.At the same time,a potential new species(Gxun-T66)was found,and the similarity with the discovered strains was only 98.49% .The results of plant growth-promoting and biocontrol effect showed that 34 strains were phosphorus-solubilizing strains,31 strains were nitrogen-fixing strains,20 strains were IAA-producing strains and 17 strains were siderophore-secreting strains.Among them,strain Burkholderia territorii Gxun-T33 had the strongest ability to dissolve phosphorus and to secrete siderophore;29 strains had obvious inhibition effect on Fusarium oxysporum f.sp.Cubense,among which strain Bacillus siamensis Gxun-T25 had the best inhibition effect,with an inhibition rate of 69.67% .The results of the en-zyme activity showed that there were 56 protease-producing strains,49 amylase-producing strains,48 cellulase-producing strains and 34 strains producing three kinds of enzyme activities at the same time,accounting for 52.31% of the isolated strains.[Conclusion]The mangrove plant A.ebracteatus is rich in microbial resources and has the activities of promoting growth,biocontrol effect and enzyme production.At the same time,a potential new species has been.
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