宁夏白芨滩自然保护区苦豆子内生放线菌多样性及其分布

Diversity and distribution of endophytic actinomycetes strains in Sophora alopecuroides L. from Baijitan Nature Reserve of Ningxia

摘要:

【目的】探索宁夏干旱荒漠区苦豆子内生放线菌的多样性及区系组成，为苦豆子内生放线菌的合理开发和利用提供理论依据。【方法】从宁夏白芨滩自然保护区不同植被和土壤类型的6个样区采集健康苦豆子样品30份，采用组织匀浆法从苦豆子植株的根部、茎部、叶部和种子中分离内生放线菌，根据培养性状、菌落、孢子等的形态特征和16S rRNA基因序列分析对分离菌株进行鉴定；根据苦豆子内生放线菌的相对频率、物种多样性指数、丰富度指数和相似性系数分析其区系组成特点。【结果】从30份苦豆子样品中，共分离得到内生放线菌111株，这些菌株分属于链霉菌属(Streptomyces)、拟诺卡氏菌属(Nocardiopsis)、普劳斯氏菌属(Prauserella)、Actinophytocola、微杆菌属(Microbacterium)、束丝放线菌属(Actinosynnema)、嗜热油菌属(Thermoleophilum)、糖霉菌属(Glycomyces)和糖丝菌属(Saccharothrix) 9个属，其中链霉菌属(Streptomyces)和拟诺卡氏菌属(Nocardiopsis)为优势属。苦豆子内生放线菌的分布具有一定的组织特异性，根和种子中的内生放线菌数量高于茎和叶。植被类型中，沙生植被草原(样区Ⅳ)分离的苦豆子内生放线菌物种多样性指数最高，而荒漠草原(样区Ⅴ)最低。荒漠草原(样区Ⅴ)和林地(样区Ⅵ)内生放线菌群落有密切的相似性。【结论】苦豆子体内含有丰富的内生放线菌资源，其内生放线菌具有很高的宿主特异性，而且其分布受生境影响。

Abstract:

[Objective] The diversity and microflora composition of endophytic actinomycetes from Sophora alopecuroides L. in arid and desolate areas of Ningxia were analyzed, which could also provide research methods and theory on rational development and use of endophytic actinomycetes from Sophora alopecuroides L.. [Methods] The endophytic actinomycetes were separated and cultivated from 30 samples of healthy roots, stems, leaves and seeds of Sophora alopecuroides L. by tissue homogenate in six sample plots, where were sampled from different vegetations and soil types in Baijitan Nature Reserve of Ningxia. Endophytic actionmycetes were classified according to their morphological characteristics of culture, bacterial colonies and spores and 16S rRNA gene sequences analysis. Relative frequency (Rf), Shannon-wiener index (F), Margalef index (D) and Sorenson’s similarity coefficient (Cs) were calculated to analyze their characteristics of microflora composition. [Results] 111 endophytic actinomycetes were isolated from 30 samples, and they belong to Streptomyces, Nocardiopsis, Prauserella, Actinophytocola, Microbacterium, Actinosynnema, Thermoleophilum, Glycomyces and Saccharothrix respectively, Streptomyces and Nocardiopsis were dominant genera. The distribution of endophytic actinomycetes from Sophora alopecuroides L. has some degree of tissue preference. Quantities of endophytic actinomycetes from roots and seeds of Sophora alopecuroides L. were more than ones of stems and leaves for the same plant. In different vegetations types, Shannon-wiener index (H′) of endophytic actionmycetes from Sophora alopecuroides L. were most significantly in the sandy weeds (sample Ⅳ) and least in desert steppes (sample Ⅴ). The community of endophytic actinomycetes from Sophora alopecuroides L. of desert steppe (sample Ⅴ) and woodland (sample Ⅵ) has closely similarity. [Conclusion] From the experiment we can see that Sophora alopecuroides L. have abundant resources of endophytic actinomycetes, the species diversity of endophytic actinomycetes communities is affected both by its host preference and by its different habitats.