Memuro Research Station, Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization.
Faculty of Agriculture, Kagoshima University.
Microbes Environ. 2023;38(1). doi: 10.1264/jsme2.ME22071.
To investigate functional plant growth-promoting rhizobacteria in sugar beet, seasonal shifts in bacterial community structures in the lateral roots of sugar beet were examined using amplicon sequencing ana-lyses of the 16S rRNA gene. Shannon and Simpson indexes significantly increased between June and July, but did not significantly differ between July and subsequent months (August and September). A weighted UniFrac principal coordinate ana-lysis grouped bacterial samples into four clusters along with PC1 (43.8%), corresponding to the four sampling months in the order of sampling dates. Taxonomic ana-lyses revealed that bacterial diversity in the lateral roots was exclusively dominated by three phyla (Actinobacteria, Bacteroidetes, and Proteobacteria) in all samples examined. At the lower taxonomic levels, the dominant taxa were roughly classified into three groups. Therefore, the relative abundances of seven dominant genera (Janthinobacterium, Kribbella, Pedobacter, Rhodanobacter, Sphingobium, Sphingopyxis, and Streptomyces) were the highest in June and gradually decreased as sugar beet grew. The relative abundances of eight taxa (Bradyrhizobiaceae, Caulobacteraceae, Chitinophagaceae, Novosphingobium, Phyllobacteriaceae, Pseudomonas, Rhizobiaceae, and Sphingomonas) were mainly high in July and/or August. The relative abundances of six taxa (unclassified Comamonadaceae, Cytophagaceae, unclassified Gammaproteobacteria, Haliangiaceae, unclassified Myxococcales, and Sinobacteraceae) were the highest in September. Among the dominant taxa, 12 genera (Amycolatopsis, Bradyrhizobium, Caulobacter, Devosia, Flavobacterium, Janthinobacterium, Kribbella, Kutzneria, Pedobacter, Rhizobium, Rhodanobacter, and Steroidobacter) were considered to be candidate groups of plant growth-promoting bacteria based on their previously reported beneficial traits as biopesticides and/or biofertilizers.
为了研究糖甜菜中的功能促生根际细菌，本研究采用 16S rRNA 基因扩增子测序分析方法，检测了糖甜菜侧根中细菌群落结构的季节性变化。香农和辛普森指数在 6 月至 7 月间显著增加，但在 7 月至随后的 8 月和 9 月间无显著差异。加权 UniFrac 主坐标分析将细菌样本按采样时间分组为 4 个聚类，与 PC1（43.8%）相对应，共 4 个采样月。分类分析显示，在所研究的所有样本中，侧根细菌多样性仅由 3 个门（放线菌门、拟杆菌门和变形菌门）主导。在较低的分类水平上，优势类群大致分为 3 组。因此，7 个优势属（链霉菌属、珊瑚菌属、鞘氨醇单胞菌属、黄杆菌属、慢生根瘤菌属、节杆菌属和链霉菌属）的相对丰度在 6 月最高，随着甜菜的生长而逐渐降低。8 个类群（根瘤菌科、鞘氨醇杆菌科、动胶菌科、新鞘氨醇单胞菌属、叶杆菌科、假单胞菌属、根瘤菌科和鞘氨醇单胞菌属）的相对丰度主要在 7 月和/或 8 月较高。6 个类群（未分类的根瘤菌科、噬纤维菌科、未分类的γ-变形菌纲、海杆菌科、未分类的黏球菌目和辛杆菌科）的相对丰度在 9 月最高。在优势类群中，有 12 个属（拟无枝酸菌属、慢生根瘤菌属、柄杆菌属、戴沃斯氏菌属、黄杆菌属、链霉菌属、珊瑚菌属、克吕伯氏菌属、鞘氨醇单胞菌属、根瘤菌属、黄杆菌属和类固醇杆菌属）被认为是具有生物防治剂和/或生物肥料有益特性的候选促生细菌属。
