The Diversity Of Root Zone Soil Bacteria And Endophytic Bacteria Of Moso Bamboo And Screening Of Growth-promoting Endophytic Bacteria

We analyzed the bacteria in root zone soil of Moso Bamboo(Phyllostys edulis)and endophytic bacteria in the bamboo by the high flux 454 GS-FLX pyrophosphate sequencing technologies.Approximate 250,237 16S rDNA sequences were generated from seven soil samples and seven tissue samples.We identified members of the bacterial community based on the sequences using RDP classifier and found evidence for 26 Orders:Actinomycetales,Rickettsiales,Burkholderiales,Enterobacteriales,Rhizobiales,Pseudomonadales,Lactobacillales,Rhodospirillales,Acidobacteriales,Sphingomonadales,Solibacterales,Xanthomonadales,Acidimicrobiales,Neisseriales,Bacillales,Pasteurellales,Flavobacteriales,Myxococcales,Caulobacterales,Solirubrobacterales,Saprospirales,Clostridiales,Legionellales,Bacteroidales and provisional Ellin329,provisional Ellin6513.Actinomycetales,Rhizobiales and Ellin6513 account for the majority of the bacterial biomass in the root zone soil of the bamboo.Enterobacteriales widely exists in the bamboo tissues.We analyzed the bacterial diversity of endophytic bacteria and bacteria in soils collected over seven months.The results showed that the bacterial community structure in the root zone soil does not significantly change over the course of the year or the bamboo development,the bacterial community structure in bamboo rhizome are close to the that in bamboo root zone soil.There were significant differences of bacteria community structure among endophytic bacteria,bamboo pole endophytic bacteria and the root zone soil bacteria.Endophytic bacteria community structure in bamboo changed with the development of the bamboo.The culturable endophytic bacteria from the bamboo were isolated with the traditional bacterial isolation and culture methods and identified with the colony characteristics and sequence analysis of 16S rDNA sequences.82 endophytic bacteria strains belonging to 47 species in 26 genera were isolated from the root,rhizome,stem and leaves of Moso Bamboo from Wuyi Mountain,and the Jiangle and Changting regions.There were significant differences in the composition of the culturable endophytic bacteria isolated from different areas and tissues.The dominant bacteria strains from the Wuyi Mountain samples were Arthrobacter,Staphylococcus,Bacillus and Enterobacter,while the dominant bacteria from the Jiangle samples were Bacillus,Staphylococcus and Curobacterium,and the dominant bacteria in the Changting samples were Alcaligenes,Pseudomonas,Staphylococcus and Bacillus.Our results demonstrate the abundant diversity of endophytic bacteria in Moso Bamboo,Potassium-solubilizing activity screening for the endophytic bacteria,the results showed that twenty endophytic phosphorus and potassium-solubilizing bacteria were screened from 82 bamboo plants,among which the CT-B09-2,WYS-A01-1 and JL-B06 had higher activities in decomposing organophosphates.Three species showed a decomposition diameter/colony diameter(D/d)of 5.05,4.19 and 2.95 respectively,and a solubilizing activity of 81.77 mg/L,77.85 mg/L and 63.69 mg/L respectively.JL-B06,WYS-A01-1 and CT-B09-2 had higher activities in decomposing inorganic phosphorus,with a decomposition diameter/colony diameter(D/d)of 2.34,2.12 and 1.82 respectively,and a solubilizing activity of 30.58 mg/L,38.89 mg/L and 48.35 mg/L respectively.CT-B21,WYS-A03-1 and JL-B06 had higher activities in decomposing potassium,with a decomposition diameter/colony diameter(D/d)of 3.37,4.84 and 4.33 respectively,and a solubilizing activity of 2.81 mg/L,2.54 mg/L and 2.46 mg/L respectively.The 16S rDNA sequence analysis showed that the 20 phosphorus and potassium solubilizing bacteria belong to 14 species from 10 genera,and mainly consist of Alcaligenes,Enterobacter and Bacillus.Bamboo has extremely rich resources of growth-promoting endophytic bacteria.We studied the colonization of growth promotion strains CT-B09-2、JL-B06 and WYS-A01-1 inside the bamboo,and gained the mutant strains of them by used the rifampicin(300μg/ml)natation,Through the methods of irrigation-root and axillary injections inoculating potted bamboo seedling,then separated the mutant strains from the bamboo root,stem and leaf regularly,and identified them.The results showed these growth promotion strains can live in bamboo and colonization in the root,stem and leaf.The growth-promoting endophytic strains can improve the bamboo photosynthesis.After treated with growth-promoting endophytic bacteria,photosynthetic rate,transpiration rate and stomatal conductance of bamboo were higher than that of the control.The growth-promoting endophytic bacteria can improved the bamboo chlorophyll content,enhanced the activity of protective enzyme,and improved the bamboo response to adverse environmental conditions.After treated with growth-promoting endophytic bacteria,CAT activity,SOD activity,POD activity,soluble protein content and soluble sugar content of the bamboo were also higher than that of the control,while the MDA content was lower.