| The community diversity of endophytic bacteria (CDEB) in Panax ginseng root was investigated by using culture-independent and culture-dependent approaches. The differences of CDEB for one congeneric ginseng root sampled from two regions and different growth stages were compared with constructions of 16S rDNA clone library and amplified DNA restriction analysis (ARDRA). Some novel bacterial species inhabiting the interior of ginseng roots were isolated and identified.Congeneric ginseng roots that have grown for 3 years were sampled from Fusong County in Jilin Province (FS), the original habitat, and from Institute of Medicinal Plant Department (IMPD) of Chinese Academy of Medical Sciences which lies in Beijing. Samples were strictly surface-sterilized followed by CTAB DNA Extraction Protocol to obtain their genome DNA respectively. To construct 16S rDNA clone libraries, primers 799f and 1492r were selected to amplify 16S rDNA segments. Thirty five OTUs, including 274 positive clones, were assigned according to their band pattern similarity in IMPD clone library. The representatives of each OTU were sequenced. The results showed that γ-Proteobacteria was the most dominant group (13 OTUs, 51.09% of the total clones), followed by α-Proteobacteria (10 OTUs, 37.59% of the total clones). A total of 286 positive clones were obtained in FS clone library, in which 130 clones were assigned to 47 OTUs according to ARDRA patterns. 10 (43 clones) out of 47 OTUs had most identity with uncultured bacteria, and 14 OTUs (37 clones) had identity with CFB (Flexibacter/Cytophaga/Bacteroides). CFB group was the most dominant group in the known species. Proteobacteria (19 OTUs, 35 clones) were only accounted for 26.9% and classified into α-, β-, and γ proteobacteria. In FS libray, 147 clones were highly homologous to chloroplast small sub-unit 16S rDNA and 1 clone was homologous to mitochondrion small sub-unit 18S rDNA. 8 chimeric DNA sequences were checked in this library and 3 OTUs (14clones) belonged to chlamydiae.Congeneric ginseng samples from different regions, different growth stages, and different culture media were used to isolate endophytic bacteria from ginseng roots. Most of Bacillus were isolated from IMPD samples on LB medium in 2005. Four of them had potential as new bacteria species. However, plenty of pseudomonas were isolated from free-nitrogen Doberener medium from the same samples. Pseudomonas spp. and Variovorax spp. as the dominantspecies were isolated on both LB medium and free-nitrogen Doberener medium from IMPD samples in 2006. Variovorax, Leifsonia and Mycobacterium from FS samples were isolated on LB medium and Variovorax spp. and Agrobacterium spp. were isolated on free-nitrogen Doberener medium in 2005.Two strains (strains ge10 and ge14) isolated on LB medium from IMPD samples were studied according to a polyphasic approach. The results showed that they were novel and different species subject to the genus Bacillus. One strain (stain wged11) isolated on free-nitrogen Doberener medium from FS samples was also explored according to a polyphasic approach. The data indicated that wged11 containing the unusual ω-Cyclohexylundecanoic acid was a novel species of the genus Leifsonia.In this study the antagonistic activities of 7 endophytic bacterial strains (ge05, ge10, ge12, ge14, ge18, ge21and ge24) from IMPD on PDA media were assayed. The results showed that two Bacillus strains (ge10 and ge14) were antagonistic to Cylindrocarpon destructans. Paenibacillus strain (ge21) was antagonistic to Rhizoctonia solani, Phytophthora cactorum and Pyricularia oryzae.Three endophytic bacterial strains (wged11, ge10, ge14) from ginseng roots had been identified as potential novel specieses.
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