Function of polyamines in growth regulation of rhizobia in host and rhizosphere

多胺在宿主和根际根瘤菌生长调节中的作用

基本信息

批准号：
06660082
负责人：
OZAWA Takashi
金额：
$ 0.96万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

1.Soybean plants accumulated sufficient putrescine and spermidine in their nodules to inhibit the growth of Bradyrhizobium japonicum.2.Another substance that inhibits the growth of B.japonicum strains was isolated from soybean roots, and was identified as 4,7-dihydroxyisoflavone, daizein. The growth inhibition of bacteroids by daizein was depressed by spermidine.3.The following results suggest that H_2O_2 derived from the oxidative deamination of spermidine is responsible for the inhibitory effect of spermidine.1) Bacterois were sensitive to H_2O_2.2) The addition of catalase depressed the growth inhibition of spermidine.3) There was a correlation between the tolerances to H_2O_2 and spermidine in many B.japonicum strains.4) Spermidine resistant mutants of B.japonicum gained resistance to the inhibitory efrect of H_2O_2.4.The results in this study suggest that spermidine is concerned in the inhibition of nitrogen fixation activity of nodules by nitrate.5.Amine oxidase was purified from soybean seedling roots. This enzyme was classified into the type I amine oxidase. The experiments using this purified enzyme suggest that amine oxidase located on the surface of bacteroids catalyzes the oxidative deamination or polyamines, and the produced H_2O_2 cases the growth inhibition of bacteroids.6.Bacterial density in the homogenate of nodules did not decrease during the incubation of the homogenate, although there was enough amine oxidase and polyamines in the homogenate to inhibit the growth of bacteroids.The results obtained in this study suggest a mechanism regulating amine oxidase activity to control the density of bacteroids in the host plant.

1.大豆植株在其根瘤中积累了足够的腐胺和亚精胺，以抑制慢生根瘤菌的生长。2.从大豆根中分离出另一种抑制日本慢生根瘤菌菌株生长的物质，经鉴定为4,7-二羟基异黄酮，大豆黄酮。大豆甙元对类杆菌生长的抑制作用被亚精胺抑制。3.以下结果表明亚精胺的抑制作用是由亚精胺氧化脱氨基产生的H_2O_2造成的。1)细菌对H_2O_敏感2)过氧化氢酶的添加降低了亚精胺的生长抑制作用。3)许多日本芽孢杆菌菌株对H_2O_2和亚精胺的耐受性之间存在相关性。4)抗亚精胺的B.japonicum突变体对H_2O_2的抑制作用产生了抗性。2.4.本研究结果表明亚精胺参与了硝酸盐对根瘤固氮活性的抑制作用。5.从大豆幼苗根中纯化了胺氧化酶。该酶被分类为I型胺氧化酶。使用该纯化酶进行的实验表明，位于类菌体表面的胺氧化酶催化氧化脱氨或多胺，产生的H_2O_2对类菌体的生长有抑制作用。 6.在培养过程中，结节匀浆中的细菌密度没有降低。尽管匀浆中有足够的胺氧化酶和多胺来抑制类菌的生长。本实验中获得的结果研究提出了一种调节胺氧化酶活性的机制来控制宿主植物中类菌的密度。