| Using microbial dilution plate counting cultivation method, the rhizosphere soilmicrobial quantity and enzyme activity and their relations of five kinds of apple rootstocks (M.hupehensis Rehd., M. micromalus Makino., M. prunifolia(Willd) Borkh., M. sievesii(Ledeb.)Roemer. and M. baccata Borkh.) were analyzed in a short-term pot experiment. One fieldexperiment was conducted to investigate the effects of grassing (Trifolium repens and Loliumperenne) and mulching (straw mulch) on rhizosphere soil microbial quantity and functionaldiversity in young 'Fuji'apple orchard by using plate count method and Biolog micro-platetechnique. Soil samples were collected from81apple orchards in12different provinces andcities. The microbial characteristics of apple orchard in major production areas of China werestudied by microbial cultivation. Yeast diversity of the Fuji apple orchard was studied by26SrDNA Dl/D2domain sequence analysis and the combination of morphology. Based onphenotypic and physiological characteristics and sequence analyses of the18S rRNA gene,internal transcribed spacer (ITS) regions and26S rRNA gene D1/D2domain. The nameKazachstania taianensis sp. nov. and Kwoniella shandongensis sp. nov. are proposed. Themain results were followed:1. The number of microbial physiological groups in rhizosphere soil under differentvarieties of apple rootstocks were significantly differences, and bacteria was dominant,followed by actinomycetes, fungi at least. Different varieties of apple rootstocks rhizospheresoil invertase, phosphatase, urease and catalase activity varied. Pearson correlation analysisindicated that certain correlation existenced between soil microbial amount and soil enzymeactivities. The microbial biodiversity indices in rhizosphere soil were different among applerootstocks, were as follows: M. sievesii(Ledeb.) Roemer> M. hupehensis Rehd.> M.micromalus Makino.> M. prunifolia(Willd) Borkh.> M. baccata Borkh.2. Compared with traditional farming method, grassing and mulching measures couldsignificantly improve the soil nutrient content and soil microorganisms in rhizosphere of young apple, and bacteria was dominant, followed by actinomycetes, fungi at least, andbacteria, fungi, actinomycetes, nitrogen-fixing bacteria, cellulose-degrading bacteria and totalmicroorganisms quantity was significantly higher than the conventional farming control.Pearson correlation analysis showed that significant correlation were existenced between soilmicrobial quantity and soil nutrient content. Grassing and mulching measures can alsoincrease the capacity to utilize carbon substrate and the biodiversity and evenness of soilmicrobial community, were as follows: Trifolium repens> Lolium perenne> straw mulch>clean tillage.3. The advantages of soil microbial physiological groups were different in each appleorchard in different regions of China. Bacteria was in the highest proportion in the appleorchard. Pearson correlation analysis indicated that significantly positive correlationexistenced between soil microbial diversity index and soil organic matter content. Soilmicrobial diversity index was different in each apple orchard between different provinces wasas follows: Heilongjiang> Yunnan> Xinjiang> Shandong> Beijing> Ningxia> Shanxi>Liaoning> Hebei> Henan> Gansu> Shanxi. Cluster analysis the number of microorganismsof different apple orchards can be divided into three groups: Heilongjiang, Liaoning; Xinjiang,Yunnan, Shaanxi, Gansu, Shanxi, Ningxia; Hebei, Shandong, Beijing, Henan, consisted withthe status of the major apple producing areas divided by the climate and ecological suitabilitystandards.4. Yeast is abundant in the Fuji orchard. The difference of yeast species between the twoorchards is significant, which contain different dominant genera yeast, respectively. A total of129yeast strains belonging to21species in13genera were isolated from samples collectedfrom Fuji apple orchards in Beijing. The dominant genera identified were Pichia (4species),Cryptococcus (4species) and Pseudozyma (3species). Among the yeast species identified,57.1%were ascomycetous yeasts belonging to12species in8genera. A total of291yeaststrains belonging to26species in13genera were isolated from samples collected from Fujiapple orchards in Shandong province. The dominant genera identified were Candida (6species), Pichia (4species) and Cryptococcus (3species). Ascomycetous yeast species werealso dominant, accounting for65.4%(17species belonging to7genera) of the speciesidentified from the Shangdong strains. 5. Three teleomorphic ascomycetous yeast strains (TA11TR-1T, TA11TR-4andTA11TR-6) isolated from the orchard soil from Tai'an, Shandong province, China, wererevealed to represent a novel species within the genus Kazachstania based on phenotypiccharacterization and sequence analyses of the18S rRNA gene, internal transcribed spacer(ITS) regions and26S rRNA gene D1/D2domain. The name Kazachstania taianensis sp. nov.(type strain TA11TR-1T=AS2.4160T=CBS11405T) is proposed. K. taianensis sp. nov. wasclustered in a branch together with Kazachstania sinensis, Kazachstania naganishii and theKazachstania telluris complex with moderate bootstrap support in the neighbor-joining treeconstructed from combined18S and D1/D2sequences. The new species possessed specialITS1(338bp) and ITS2(488bp) sequences. The total length of the ITS-5.8S rDNA regionof the species was983bp, being much longer than those of other ascomycetous yeast speciesdescribed so far.6. Four basidiomycetous yeast strains (Y13-1T, Y2-1, Y6-3and Y8-2) isolated from anapple orchard in Tai'an, Shandong province, China. Phylogenetic analysis based on26S rRNAgene D1/D2domains and ITS regions revealed that those strains were located in theKwoniella clade in the Tremellomycetes and were closely related to Cryptococcus cuniculiout Kwoniella heveanensis and clearly distinct from the latter species. Therefore, a newspecies, named as Kwoniella shandongensis sp. nov.(type strain Y13-1T=CGMCC2.04458T=CBS12478T) is proposed. The MycoBank number of the new species is MB564868.
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