| Populus xeuramericana、Populus xeuramericanacv. Robusta94which was transgenosis of Populus xeuramericana,Populus tomentosawhich was modified,are two types of poplar clonal cultivars which were used more promotion and application,have much important value of production and application in forestry cultivation and woods production.In order to understand the potential pathogenic bacteria, biological bacteria and other benefical microorganism of Populus tomentos and Populus xeuramericana,and found new bacteria speices to provide datas for evolutionary, also made a basis for controlling of poplar pest and the development and utilization of benefical microorganism, the reseach about the endophytic bacteria species diversity, community composition, seasonal fluctuations of dominate population in cortex tissues of two types of poplars which isolated from two types of poplars in2011-2012were studied by the traditional bacterial culturing and combined with physiology characteristics and16S rDNA sequence identifications and analysis of phylogenetic.And two new bacteria species of isolates identificated by the morphology observation, physiology and biochemistry characteristics analysis,DNA-DNA hybridization and whole-cell fatty acids assay and other chemical and molecular biology methods.(1)A total of532isolates obtained from the cortex tissues of two type of poplars with8times which were sequenced and analysed by their16S rDNA sequence,they have been placed into31genera and69species,17genera and32species were got from Populus×euramericana, Rhizobium、Sphingomonas and Microbacterium were predominate community;16genera and22species were got from Populus xeuramericana cv. Robusta94, Rhizobium and Microbacterium were predominate community;18genera snd30species were got from Populus tomentosa, Rhiobium、Bacillus、Aurantimonas and Cellulomonas were predominate community.The results shows that the abundance and diversity of endophytic bacteria in cortex tissues of poplars.On the whole, Rhizobium was the most remarkable dominate population among them, but not absolutely consistent with each other. The predominate population of Populus xeuramericana was consistent with Populus xeuramericana cv. Robusta94, but was different with Populus tomentosa, which shows that changing the gene of poplar, the predominate population of endophytic bacteria in same cultivar wouldn’t happen larger variation, but different cultivar would appear difference.(2)The seasonal varieties of the number of endophytic bacteria isolates from two types of poplars was not consisitently in a whole, the variation of Populus xeuramericana was consistent with Populus xeuramericana cv. Robusta94, but was different with Populus tomentosa, shows that the number of endophytic bacteria in warm seasons were higher than in cold seasons.And the predominate population of two types of poplars were differnent in four seasons, were fluctuated with the varies of season.They were display consistent in winter that Rhizobium was their predominate population,which shows the quantity and species of endophytic bacteria of two types of poplars variation was appeared identinity and diffemence as the fluctuating of seasons.(3) The strain13BinDT and10-107-8T were isolate from the cortex of Populus xeuramericana. their similarity were96.61%and97.40%compare with Lampropeida hyaline JCM2138T snd Microbacterium halotolerans JCM13013T through the16S rDNA sequence analysis.And they were belong to the genu Lampropedia and Microbacterium by the morphology,physiology characteristic,whole cell fatty acids content analysis,but they were not same as L.hyalina and M.halotolerans in some physiology characteristic, phylogeny about16S rDNA sequence and gyrB(gyrase gene), DNA-DNA hybridization and G+C contents.They were suggest named as Lampropedia puyangensis nov.sp and Microbacterium populi nov.sp.,the former was Gram-negative bacteria,the latter was Gram-positive bacteria. Both grew on NA in pH7.0,30℃.And the contents of fatty acids of13BinD T were C16:o, C16:1, C18:ω7c, the contents of G+C was57mol%,otherwise,the contents of fatty acids of10-107-81were anteiso-C15:0,iso-C16:0, anteiso-C17:0, the contents of G+C was57.28mol%. |
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