Sugano Atsuo, Tsuchimoto Hidetaka, Cho Tun Cho, Kimura Makoto, Asakawa Susumu
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan.
Archaea. 2005 Dec;1(6):391-7. doi: 10.1155/2005/582597.
The succession and phylogenetic profiles of methanogenic archaeal communities associated with rice straw decomposition in rice-field soil were studied by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis followed by 16S rDNA sequencing. Nylon bags containing either leaf sheaths or blades were buried in the plowed layer of a Japanese rice field under drained conditions during the off-crop season and under flooded conditions after transplanting. In addition, rice straw samples that had been buried in the rice field under drained conditions during the off-crop season were temporarily removed during spring plowing and then re-buried in the same rice field under flooded conditions at transplanting. Populations of methanogenic archaea were examined by amplification of the 16S rRNA genes in the DNA extracted from the rice straw samples. No PCR product was produced for samples of leaf sheath or blade prior to burial or after burial under drained conditions, indicating that the methanogen population was very small during decomposition of rice straw under oxic conditions. Many common bands were observed in rice straw samples of leaf sheath and blade during decomposition of rice straw under flooded conditions. Cluster analysis based on DGGE patterns divided methanogenic archaeal communities into two groups before and after the mid-season drainage. Sequence analysis of DGGE bands that were commonly present were closely related to Methanomicrobiales and Rice cluster I. Methanomicrobiales, Rice cluster I and Methanosarcinales were major members before the mid-season drainage, whereas the DGGE bands that characterized methanogenic archaeal communities after the mid-season drainage were closely related to Methanomicrobiales. These results indicate that mid-season drainage affected the methanogenic archaeal communities irrespective of their location on rice straw (sheath and blade) and the previous history of decomposition during the off-crop season.
采用聚合酶链反应-变性梯度凝胶电泳（PCR-DGGE）分析，随后进行16S rDNA测序，研究了与稻田土壤中稻草分解相关的产甲烷古菌群落的演替和系统发育概况。在非作物生长季节，将装有叶鞘或叶片的尼龙袋埋入日本稻田的耕层，排水条件下进行；移栽后则在淹水条件下进行。此外，在非作物生长季节排水条件下埋入稻田的稻草样品，在春季翻耕时临时取出，然后在移栽时重新埋入同一稻田的淹水条件下。通过扩增从稻草样品中提取的DNA中的16S rRNA基因来检测产甲烷古菌的种群。在埋葬前或排水条件下埋葬后的叶鞘或叶片样品均未产生PCR产物，表明在有氧条件下稻草分解过程中产甲烷菌种群非常小。在淹水条件下稻草分解过程中，叶鞘和叶片的稻草样品中观察到许多共同条带。基于DGGE图谱的聚类分析将产甲烷古菌群落分为季中排水前后两组。常见的DGGE条带序列分析与甲烷微菌目和水稻菌群I密切相关。季中排水前，甲烷微菌目、水稻菌群I和甲烷八叠球菌目是主要成员，而季中排水后表征产甲烷古菌群落的DGGE条带与甲烷微菌目密切相关。这些结果表明，季中排水影响了产甲烷古菌群落，无论其在稻草（叶鞘和叶片）上的位置以及非作物生长季节之前的分解历史如何。
