著者

Dongyan Liu Kanako Tago Masahito Hayatsu Takeshi Tokida Hidemitsu Sakai Hirofumi Nakamura Yasuhiro Usui Toshihiro Hasegawa Susumu Asakawa

出版者

日本微生物生態学会 / 日本土壌微生物学会 / Taiwan Society of Microbial Ecology / 植物微生物研究会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME16066, (Released:2016-09-07)

被引用文献数

23

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Elevated concentrations of atmospheric CO2 ([CO2]) enhance the production and emission of methane in paddy fields. In the present study, the effects of elevated [CO2], elevated temperature (ET), and no nitrogen fertilization (LN) on methanogenic archaeal and methane-oxidizing bacterial community structures in a free-air CO2 enrichment (FACE) experimental paddy field were investigated by PCR-DGGE and real-time quantitative PCR. Soil samples were collected from the upper and lower soil layers at the rice panicle initiation (PI) and mid-ripening (MR) stages. The composition of the methanogenic archaeal community in the upper and lower soil layers was not markedly affected by the elevated [CO2], ET, or LN condition. The abundance of the methanogenic archaeal community in the upper and lower soil layers was also not affected by elevated [CO2] or ET, but was significantly increased at the rice PI stage and significantly decreased by LN in the lower soil layer. In contrast, the composition of the methane-oxidizing bacterial community was affected by rice-growing stages in the upper soil layer. The abundance of methane-oxidizing bacteria was significantly decreased by elevated [CO2] and LN in both soil layers at the rice MR stage and by ET in the upper soil layer. The ratio of mcrA/pmoA genes correlated with methane emission from ambient and FACE paddy plots at the PI stage. These results indicate that the decrease observed in the abundance of methane-oxidizing bacteria was related to increased methane emission from the paddy field under the elevated [CO2], ET, and LN conditions.

著者

Tsubasa Ohbayashi Yong Wang Luciano Nobuhiro Aoyagi Shintaro Hara Kanako Tago Masahito Hayatsu

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.38, no.4, pp.ME23068, 2023 (Released:2023-12-13)

参考文献数

67

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Nitrification is a key process in the biogeochemical nitrogen cycle and a major emission source of the greenhouse gas nitrous oxide (N2O). The periplasmic enzyme hydroxylamine oxidoreductase (HAO) is involved in the oxidation of hydroxylamine to nitric oxide in the second step of nitrification, producing N2O as a byproduct. Its three-dimensional structure demonstrates that slight differences in HAO active site residues have inhibitor effects. Therefore, a more detailed understanding of the diversity of HAO active site residues in soil microorganisms is important for the development of novel nitrification inhibitors using structure-guided drug design. However, this has not yet been examined. In the present study, we investigated hao gene diversity in beta-proteobacterial ammonia-oxidizing bacteria (β-AOB) and complete ammonia-oxidizing (comammox; Nitrospira spp.) bacteria in agricultural fields using a clone library ana­lysis. A total of 1,949 hao gene sequences revealed that hao gene diversity in β-AOB and comammox bacteria was affected by the fertilizer treatment and field type, respectively. Moreover, hao sequences showed the almost complete conservation of the six HAO active site residues in both β-AOB and comammox bacteria. The diversity of nitrifying bacteria showed similarity between hao and amoA genes. The nxrB amplicon sequence revealed the dominance of Nitrospira cluster II in tea field soils. The present study is the first to reveal hao gene diversity in agricultural soils, which will accelerate the efficient screening of HAO inhibitors and evaluations of their suppressive effects on nitrification in agricultural soils.

著者

Tsubasa Ohbayashi Raynald Cossard Gaëlle Lextrait Takahiro Hosokawa Vincent Lesieur Kazutaka Takeshita Kanako Tago Peter Mergaert Yoshitomo Kikuchi

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.37, no.3, pp.ME22042, 2022 (Released:2022-08-11)

参考文献数

56

被引用文献数

7

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Many stinkbugs in the superfamily Coreoidea (Hemiptera: Heteroptera) develop crypts in the posterior midgut, harboring Caballeronia (Burkholderia) symbionts. These symbionts form a monophyletic group in Burkholderia sensu lato, called the “stinkbug-associated beneficial and environmental (SBE)” group, recently reclassified as the new genus Caballeronia. SBE symbionts are separated into the subclades SBE-α and SBE-β. Previous studies suggested a regional effect on the symbiont infection pattern; Japanese and American bug species are more likely to be associated with SBE-α, while European bug species are almost exclusively associated with SBE-β. However, since only a few insect species have been investigated, it remains unclear whether region-specific infection is general. We herein investigated Caballeronia gut symbionts in diverse Japanese, European, and North American populations of a cosmopolitan species, the Western conifer seed bug Leptoglossus occidentalis (Coreoidea: Coreidae). A mole­cular phylogenetic ana­lysis of the 16S rRNA gene demonstrated that SBE-β was the most dominant in all populations. Notably, SBE-α was rarely detected in any region, while a third clade, the “Coreoidea clade” occupied one fourth of the tested populations. Although aposymbiotic bugs showed high mortality, SBE-α- and SBE-β-inoculated insects both showed high survival rates; however, a competition assay demonstrated that SBE-β outcompeted SBE-α in the midgut crypts of L. occidentalis. These results strongly suggest that symbiont specificity in the Leptoglossus-Caballeronia symbiotic association is influenced by the host rather than geography, while the geographic distribution of symbionts may be more important in other bugs.