Investigation for functionalities of rhizo-biocomplex to minimize highly adverse conditions in association with organic sink in the rhizosphere and its utilization in agricultural use

我们在印度尼西亚加里曼丹研究了能够缓解不良土壤的根际生物系统。Burkholderia sp.从生长在中强酸性泥炭地中的白茅根际分离到的A-KA菌株，对其他根际细菌如鞘氨醇单胞菌具有一定的促生活性。从耐酸性硫酸盐土壤的水稻根际分离出的拟态伯克霍尔德氏菌抑制了引起水稻疫病的植物芽孢杆菌的生长，同时促进了根附生细菌和种子附生细菌的生长。从富含多酚的热带泥炭土中分离到的根际细菌中，含有焦性没食子酚的植物多酚能激活Burkholderia unamae CK-43B降解吲哚等N-杂环芳香化合物。在苏铁与固氮蓝藻发菜共生的珊瑚根共生体系中，二酰甘油是蓝藻识别宿主所必需的原基诱导因子。此外，我们还成功地从菠菜根中分离的耶森假单胞菌EC-S101菌株和从水稻根中分离到的根际真菌绿色木霉PS1-7菌株中分离并鉴定了信号化合物。在根际环境中，热带泥炭土中产生一氧化二氮的细菌缺失其一氧化二氮还原酶(N2OR)基因，并通过多种植物次生代谢产物影响其反硝化作用。

We investigated rhizo-biosystems that enable to mitigate adverse soils in Kalimantan, Indonesia. Burkholderia sp. strain A-KA that had been isolated from the rhizosphere of Imperata cylindrica grown in medium-strongly acidic peatland showed a growth-helper activity toward other rhizosphere bacteria, such as Sphingomonas sp. Burkholderia mimosarum isolated from rhizosphere of paddy rice tolerant to acid-sulfate soil suppressed tropolone production of B. plantarii, a bacterium causative of rice blight disease, while promoted growth of diverse root-and seed-epiphytic bacteria. Among rhizobacteria that had isolated from dipterocarpous sapling adapting to polyphenol-rich tropical peat soil, pyrogallol-containing plant polyphenols activated Burkholderia unamae CK-43B to degrade indole and some other N-heterocyclic aromatic compounds. In the coralloid root symbiotic systems between Cycas revoluta root and a nitrogen-fixing cyanobacterium Nostoc punchiforme, a diacylglycerol was found to be the principle of hormogoniu-inducing factor on the cyanobacterium necessary to its host-recognition. Also, we successfully isolated and characterized signal compounds from a rhizobacterium Pseudomonas jessenii strain EC-S101 isolated from spinach root and from a rhizosphere fungus Trichoderma virens strain PS1-7 isolated from paddy root. In the rhizosphere, nitrous oxide emitting bacteria in tropical peat soil were missing their nitrous oxide reductase (N2OR) genes, and affected its denitrification by several secondary metabolites of plants