title: Identification of active denitrifiers in rice paddy soil by DNA- and RNA-based analyses.
abstract: Denitrification occurs markedly in rice paddy fields; however, few microbes that are actively involved in denitrification in these environments have been identified. In this study, we used a laboratory soil microcosm system in which denitrification activity was enhanced. DNA and RNA were extracted from soil at six time points after enhancing denitrification activity, and quantitative PCR and clone library analyses were performed targeting the 16S rRNA gene and denitrification functional genes (nirS, nirK and nosZ) to clarify which microbes are actively involved in denitrification in rice paddy soil. Based on the quantitative PCR results, transcription levels of the functional genes agreed with the denitrification activity, although gene abundance did not change at the DNA level. Diverse denitrifiers were detected in clone library analysis, but comparative analysis suggested that only some of the putative denitrifiers, especially those belonging to the orders Neisseriales, Rhodocyclales and Burkholderiales, were actively involved in denitrification in rice paddy soil.
authors.affiliation: Department of Applied Biological Chemistry, The University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113–8657, Japan. myoshida_a@yahoo.co.jp
authors.forename: Megumi
authors.initials: M
authors.lastname: Yoshida
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishii
authors.forename: Daichi
authors.initials: D
authors.lastname: Fujii
authors.forename: Shigeto
authors.initials: S
authors.lastname: Otsuka
authors.forename: Keishi
authors.initials: K
authors.lastname: Senoo
mesh_terms: D001483:Base Sequence; D044822:Biodiversity; D042521:Burkholderiaceae / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D058440:Denitrification / Q000235:genetics*; D008969:Molecular Sequence Data; D009346:Neisseriaceae / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012275:Oryza / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D043362:Rhodocyclaceae / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017423:Sequence Analysis, RNA; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S