Effect of diverse nitrogen-fixing bacterial community inhabiting the rhizoplane of acid sulfate soil-tolerant plants on nitrogen circulation around the rhizophere.

在这项研究中，我们在无氮的软凝胶培养基中培养腐烂洗涤液作为功能根面和/或根际微生物的初步筛选，并有效和选择性地获得α-和β-变形杆菌以排除腐生性γ-变形杆菌。这些寡养和/或重氮细菌在软凝胶介质中的行为被可视化，包括它们的生物复合体的形成和三方伙伴关系。在无氮软凝胶基质中繁殖的细菌菌群在室温条件下存活的时间较长，这是由于细菌类生物膜定植和群体感应类休眠所致。因此，我们能够探索与研究根面微花群落行为相关的功能根-生物复合体的新领域。作为示范，我们从具有代表性的耐酸性硫酸盐土壤植物--野牡丹的根平面上分离和传代了两种根面细菌，分别为鞘氨醇单胞菌和洋葱伯克霍尔德氏菌，并对它们进行了16S rRNA基因测序和数据库检索。S·罗莎出现了。在强酸性条件下改变根际条件和提高根际生物复合体的氮素供应的能力。和S.Rosa一样，还有许多其他鞘氨醇单胞菌。通常从加里曼丹耐酸植物的根面分离出来的植物具有以下特点：1)有助于缓解根际分流土壤；2)根面固氮或至少调节固氮条件；3)通过根际中的镁离子调节微花种群。此外，鞘氨醇单胞菌属(Sphingomonas spp.)在寄主植物的根面和/或内部组织中具有紧密的伙伴关系和三方样的协同作用。鞘氨醇单胞菌因此有望成为根际生物复合体中氮素循环和高遗传多样性的推动力。

In this study, we cultured rot washings in nitrogen-free, soft gel medium as a primary screening of functional rhizoplane and/or rhizosphere microbes, and we efficiently and selectively obtained α- and β-proteobacteria to exclude saprophytic γ-proteobacteria. Those oligotrophic and/or diazotrophic bacteria were visualized their behaviors in the soft gel medium, including their biocomplex formation and tripartite partnerships. The bacterial flora propagated in the N-free soft gel medium of gellan gum base survived relatively longer in the medium at room temperature due to a biofilm-like colonization and quorum-sensing like dormancy. Thus, we were able to trail new area of functional rhizo-biocomplex connected to the study of behabior of rhizoplane microfloral communities. As a demonstration, we have isolated and sub-cultured two rhizoplane bacteria, Sphingomonas rosa and Burkholderia cepacia, from rhizoplane of Melastoma malabathricum, a representative acid sulfate soil-tolerant plant, and identified them with 16S rRNA gene sequencing and data base search. The S. rosa showed. abilities to alter rhizospherous conditions and also to enhance nitrogen supply from the rhizo-biocomplex in a sotrongly acidic conditions. Like S. rosa, many other Sphingomonas spp. often isolated from the rhizoplane of acid-tolerant plants in Kalimantan had characteristics of 1) contributing to reliving divert soil in the rhizosphere, 2) fixing nitrogen in the rhizoplane or at least adjusting conditions for nitrogen fixation, and 3) being regulated the microfloral population via Mg^<2+> in the rhizosphere. In addition, Sphingomonas spp. had tight partnerships and tripartite-like co-works in the rhizoplane and/or inner tissues of host plants. Sphingomonas spp. are thus expected to be a motive force for nitrogen circulation and high genetic diversity in the rhizo-biocomplex.