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Katata, Genki*; Yamaguchi, Takashi*; Watanabe, Makoto*; Fukushima, Keitaro*; Nakayama, Masataka*; Nagano, Hirohiko*; Koarashi, Jun; Tateno, Ryunosuke*; Kubota, Tomohiro
Atmospheric Environment, 298, p.119640_1 - 119640_12, 2023/04
Times Cited Count：1 Percentile：58.15(Environmental Sciences)Nakayama, Masataka; Tateno, Ryunosuke*
Plant and Soil, 17 Pages, 2023/00
Times Cited Count：0 Percentile：0.02(Agronomy)
Microbial communities within the soil surrounding plant roots (rhizosphere) are distinct from those in the non-rhizosphere soil because of root exudation and symbiosis with plant roots and play important roles in plant growth. However, seasonal variations in these rhizosphere microbial communities are not well known, especially during the plant's dormant season in cool temperate forests. 
We investigated the rhizosphere microbial communities in a cool-temperate deciduous broad-leaved forest at the growing season (mid-summer) and at the beginning and end of the plant's dormant season (early winter and early spring) using metabarcoding of prokaryotic 16S rRNA genes and fungal ITS region, microbial functional prediction, and co-occurrence network analysis. 
The rhizosphere dominant prokaryotic subgroup (occupying 19.4 
3.2% of relative read counts) had non-significant seasonal fluctuations, and their relative read counts were correlated with physicochemical properties, including pH and water content. In contrast, the relative read count of ectomycorrhizal fungi was 1.4 times higher in the rhizosphere than that in the bulk soil in mid-summer. However, the relative read counts of ectomycorrhizal fungi within rhizospheres in winter and spring (28.5 18.9% and 20.8 13.8%, respectively) were similar to that in bulk soil (25.8 18.7% and 22.4 17.1%, respectively). 
Ectomycorrhizal fungi reduced their occupancy within the rhizosphere during the plant's dormant seasons, whereas rhizosphere-dominant prokaryotic communities were stable during the seasonal change, implying the importance of prokaryotic rather than ectomycorrhizal fungal communities in the processes occurring within the rhizosphere during dormant seasons.
Nagano, Hirohiko; Nakayama, Masataka*; Katata, Genki*; Fukushima, Keitaro*; Yamaguchi, Takashi*; Watanabe, Makoto*; Kondo, Toshiaki*; Atarashi-Andoh, Mariko; Kubota, Tomohiro*; Tateno, Ryunosuke*; et al.
Soil Science and Plant Nutrition, 67(5), p.606 - 616, 2021/10
Times Cited Count：2 Percentile：19.73(Plant Sciences)We analyzed the relationships between nitrogen deposition (deposition of nitrate and ammonium ions) and soil microbial properties in a cool temperate forest surrounded by normally fertilized pasture grasslands in northern Japan. The aim of the present study was to gain the primary information on soil microbial response to moderately elevated nitrogen deposition (
10 kg N ha
y). We established three experimental plots in the forest edge adjacent to grasslands and other three plots in the forest interior at least 700 m away from the grasslands. During May to November 2018, nitrogen deposition in each plot was measured. In August 2018, litter and soil (0-5 cm depth) samples were collected from all plots to measure net nitrogen mineralization and nitrification rates as indicators of microbial activity, and microbial biomass carbon and nitrogen and various gene abundances (i.e. bacterial 16S rRNA, fungal ITS, bacterial amoA, and archaeal amoA genes) as indicators of microbial abundance and structure. Nitrogen deposition in the forest edge was 1.4-fold greater than that in the forest interior, even while the maximum deposition was 3.7 kg N ha. Nitrogen deposition was significantly correlated to the net nitrogen mineralization and nitrification rates and the 16S rRNA and bacterial amoA gene abundances. Microbial community structures were different between litter and soil samples but were similar between the forest edge and interior. Significant correlations of nitrogen deposition to the soil carbon to nitrogen ratio, and the nitrate and ammonium contents were also observed. Thus, our results show that moderately elevated nitrogen deposition in nitrogen-limited forest edges can stimulate microbial activities and abundances in soils.
Katata, Genki*; Fukushima, Keitaro*; Koarashi, Jun; Yamaguchi, Takashi*; Watanabe, Makoto*; Tateno, Ryunosuke*
no journal, ,
no abstracts in English
Nagano, Hirohiko; Atarashi-Andoh, Mariko; Fukushima, Keitaro*; Nakayama, Masataka*; Katata, Genki*; Yamaguchi, Takashi*; Watanabe, Makoto*; Kondo, Toshiaki*; Tateno, Ryunosuke*; Koarashi, Jun
no journal, ,
no abstracts in English
Katata, Genki*; Fukushima, Keitaro*; Koarashi, Jun; Yamaguchi, Takashi*; Watanabe, Makoto*; Nagano, Hirohiko; Nakayama, Masataka*; Tateno, Ryunosuke*
no journal, ,
no abstracts in English
Watanabe, Makoto*; Norisada, Masanari*; Kinose, Yoshiyuki*; Yamaguchi, Takashi*; Nakayama, Masataka*; Fukushima, Keitaro*; Tateno, Ryunosuke*; Nagano, Hirohiko; Koarashi, Jun; Katata, Genki*
no journal, ,
no abstracts in English
Katata, Genki*; Fukushima, Keitaro*; Koarashi, Jun; Yamaguchi, Takashi*; Watanabe, Makoto*; Nagano, Hirohiko; Nakayama, Masataka*; Tateno, Ryunosuke*; Kinose, Yoshiyuki*
no journal, ,
no abstracts in English
Nagano, Hirohiko*; Nakayama, Masataka; Katata, Genki*; Fukushima, Keitaro*; Yamaguchi, Takashi*; Watanabe, Makoto*; Atarashi-Andoh, Mariko; Tateno, Ryunosuke*; Hiradate, Shuntaro*; Koarashi, Jun
no journal, ,
Nakayama, Masataka; Tateno, Ryunosuke*
no journal, ,
Root exudates, carbon compounds secreted from plant fine roots, enhance nutrient cycles within root surrounding soil (rhizosphere) by stimulating microbial activities and growth. However, there is a lack of knowledge about the effect of the differences in the chemical composition of root exudates and the diversity of root exudates on the nitrogen cycle within the rhizosphere. Here, we investigated the impact of the differences in root exudates on the nitrogen cycles and microbial community using artificial root exudates (ARE). We added ARE from the simulated fine root and changed their diversity from 1 to 3 per incubation system. Soil microbial gene abundances varied among ARE types and diversity, but the differences were not statistically significant. In addition, there was a non-significant effect of ARE on nitrogen cycling processes. These results indicated that the diversity and compositions of root exudates did not affect the microbial community and nitrogen cycle for at least a short time.
Katata, Genki*; Yamaguchi, Takashi*; Watanabe, Makoto*; Fukushima, Keitaro*; Nakayama, Masataka; Nagano, Hirohiko*; Koarashi, Jun; Tateno, Ryunosuke*; Kubota, Tomohiro
no journal, ,
no abstracts in English
