Evaluation of Nitrogen-Fixing Bacteria in Southeast Asia

1)泰国研究人员在泰国酸性土壤中从大豆根瘤中分离出多种根瘤菌。这些菌株在pH 3.5或4.0下生长。与大阪大学合作，成功地将3株耐酸缓生根瘤菌转化为绿色荧光蛋白（GFP）标记。这些菌落在紫外线照射下显示绿色荧光。2)印度尼西亚研究人员从印度尼西亚豆科树木的根瘤中分离出固氮根瘤菌。这些细菌是与大阪大学、广岛大学和鹿儿岛大学合作分类的。从印度尼西亚不同产地的相思根瘤中分离的细菌被分类为elkanji慢生根瘤菌。从印度尼西亚不同地点的falcataria副蕨根瘤中分离到的菌株分为elkanil Bradyrhizobiwn、Rizizobiwn tropici以及两者之间的菌株。研究了一株耐酸菌株BTCC-B64作为氮肥替代品。菌株侵染对植株、根系和根瘤总干重的固氮作用有显著影响。3)利用菲律宾分离的游离固氮菌、固氮菌或木霉的纤维素分解真菌作为牛粪-稻壳堆肥的接种剂。接种固氮菌改善了堆肥的降解和养分含量，增加了堆肥中的接种剂负荷。4)马来西亚研究人员克隆了一种固氮革兰氏阳性细菌固氮Paenibacillus azotofixans的niflHDKTY Peron。Azospirillun是香蕉、油棕种子和蔬菜大豆的有效生物增强剂，也是香蕉的生物肥料。5)研究了日本慢生根瘤菌接种剂在越南酸性水稻土中的生存能力。

1)Thai researchers isolated various kinds of rhizobia from nodules of soy bean in acidic soils in Thailand. These strains grow at pH 3.5 or at 4.0. By collaboration with Osaka University, three acid tolerant strains of Bradyrhizobium were succeeded in transformation to tagging with the Green Fluorescence Protein (GFP). These colonies on the plates showed green fluorescence under the UV exposure.2)Indonesian researchers isolated nitrogen-fixing rhizobia from nodules of leguminous trees in Indonesia. These bacteria were classified by collaboration with Osaka University, Hiroshima University, and Kagoshima University. Bacterial strains isolated from root nodules on Acacia mangium at various locations in Indonesia were classified to Bradyrhizobium elkanji. Bacterial strains isolated from root nodules on Paraserianthes falcataria at various locations in Indonesia were classified into Bradyrhizobiwn elkanil, Rizizobiwn tropici and strains between these species. An acid tolerant strain, Bradyrhizobiwn sp. BTCC-B64 was evaluated as nitrogen fertilizer substitute. The infection of the strains were effective on the nitrogen fixation which performed by the total dried weight of plants, roots and nodules.3)Free living nitrogen-fixing bacteria, Azotobacter sp. or cellulolytic fungi of Trichoderma sp. isolated in Philippines were used as inoculant in cattle manure-rice hull compost. The inoculation with nitrogen-fixing bacteria improved the degradation and nutrient content of the materials and enhance the inoculant load in the compost.4)The niflHDKTY Peron from a nitrogen fixing gram positive bacterium, Paenibacillus azotofixans were cloned and characterized by Malaysian researchers. Azospirillun was found to be an effective bioenhancer for banana and oil palm seedings, and vegetatable soybean as well as a biofertilizer for banana.5)Survivability of the inoculant of Bradyrhizobium japonicum in acid paddy soil in Vietnam was investigated.