Expression and lateral transfer of nitrogen fixation genes in the gut of earthworms.

固氮基因在蚯蚓肠道中的表达和横向转移。

• 批准号: 15580052
• 负责人: OZAWA Takashi
• 金额: $ 2.24万
• 依托单位: Osaka Prefecture University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15580052/
• 关键词: earthworm; nitrogen fixation; fertile soil; enterobacterium; plant growth promotion; soil animal; Azospirillum; microbial community; 微生物群集構造

The contribution of an earthworm species (Amynthas vittatus) to the increase of the nitrogen content of soil was examined. Three specimens of adult earthworms were introduced into 300 g of soil (Gray Lowland soil, silty clay) supplemented with 1% carboxymethyl cellulose in a container and incubated for 32 days at 22℃ in the dark. The contents of total-N, NH_4-N and NO_3-N, and the population of aerobic nitrogen-fixing bacteria in soil significantly increased after incubation with the earthworms, while the natural abundance of ^<15>N (δ^<15>N) in soil decreased. The amount of nitrogen in the earthworms did not decrease during the incubation in the microcosm. Both acetylene reduction activity of the microcosm and incorporation of ^<15>N to soil from atmospheric ^<15>N_2 were significantly enhanced by the introduction of the earthworms into soil, though the observed increment of nitrogen in soil was much higher than the estimated one based on the nitrogen-fixing activity.The community structure of aerobic nitrogen-fixing bacteria in the soils where the earthworms had lived was estimated by both isolating NFBs from the soils and the analysis of PCR-DGGE patterns of nifH from the soils. Physiological characteristics and 16S rDNA sequence analysis showed that the isolated NFBs were classified into Azorhizobium caulinodans, Azospirillum brasilense, A.lipoferum, Klebsiella oxytoca, Pseudomonas sp., Rhizobium etli, Rosemonas faurise, Sinorhizobium morelens, and Xanthobacter sp. The number and the pattern of DGGE bands of nifH from the soil incubated with earthworms were different from those of nifH from earthworm casts and the soil in which earthworms did not live.The results obtained in the present study indicated that the earthworms increased the nitrogen content of soil, presumably due to the enhancement of the nitrogen-fixing activity of the soil from the microcosm by the earthworms.

研究了earth物种（amynthas vittatus）对土壤氮含量增加的贡献。将三种成年earth的规格引入了300克土壤（灰色低地土壤，粉质粘土）中，并在容器中补充了1％羧甲基纤维素，并在黑暗中22°孵育32天。总-N，NH_4-N和NO_3-N的含量以及与earth孵育后，土壤中有氧氮固定细菌的种群显着增加，而土壤中 ^<15> N（Δ ^ ^<15> n）的自然抽象降低。在微观环境中孵育期间，earth中的氮量不会减少。通过将earth虫引入土壤中的含量增长远高于基于氮的结构，据估计，据估计，据估计的nirobic nitrogen的结构，这两种乙烯含量的增量均高于估计的eart虫，这两种含量均高于蚀刻的earto虫，这两种含量均高于估计的nirobic nirogia ixter，这两种乙烯的含量都高得多从土壤中分离NFB，并分析来自土壤的NIFH的PCR-DGGE模式。生理特征和16S rDNA序列分析表明，孤立的NFB分类为Azorhizobium carulinodans，azospirillum Brasilense，A.liplboferum，a.liplbsiella oxytoca，Pseudomonas sp。 NIFH与earth孵化的NIFH的DGGE带的数量和模式不同于earth铸件的NIFH和NIFH的数量和未生存的土壤。在本研究中获得的结果表明，earth虫的氮含量可能增加了土壤的氮含量，这是由于ni氮量卵的增强而源于土壤的or虫活性的增强。

项目成果

Effect of the earthworm Pheretima sp.on the community of aerobic diazotrophs in an agricultural soil and the nitrogen fertility of the soil.

蚯蚓对农业土壤好氧固氮微生物群落及土壤氮素肥力的影响。

• 发表时间: 2004
• 期刊: Biotechnology for Sustainable Utilization of Biological Resources in the Tropics 17
• 作者: Ozawa;T.;Risal;C.P.;Yanagimoto;R.;Soga;Y.
• 通讯作者: Y.