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研究者情報

マスター

アカウント（マスター）

  • 氏名

    丸山　隼人(マルヤマ　ハヤト), マルヤマ　ハヤト

所属（マスター）

  • 農学研究院　基盤研究部門　生物機能化学分野

所属（マスター）

  • 農学研究院　基盤研究部門　生物機能化学分野

独自項目

syllabus

  • 2021, 生物機能化学演習Ⅰ, Seminar on Bioscience and Chemistry I, 学士課程, 農学部, 専門関連英文原書精読
  • 2021, 植物栄養学, Plant Nutrition, 学士課程, 農学部, 土壌、物質循環、植物生産、環境保全、施肥、栄養生理、栄養生態、不良土壌、根圏、植物－微生物共生
  • 2021, 生物機能化学実験Ⅱ, Laboratry Work on Bioscience and Chemistry II, 学士課程, 農学部, 植物栄養、作物栽培、水耕栽培、無機分析、菌根菌、根の形態観察、窒素、糖、デンプン、鉄、リン、カリウム

researchmap

プロフィール情報

学位

  • 博士（農学）（広島大学）
  • 修士（農学）（北海道大学）

プロフィール情報

  • 姓

    丸山

  • 名

    隼人

  • ID各種

    201701008958091666

業績リスト

研究キーワード

  • シロバナルーピン   放射性セシウム   遺伝子共発現ネットワーク   養分欠乏   トランスクリプトーム   菌根菌   植物栄養学   根分泌物   根圏   リン   

研究分野

  • 環境・農学 / 作物生産科学
  • ライフサイエンス / 植物栄養学、土壌学

経歴

  • 2016年10月 - 現在 北海道大学大学院 農学研究院 助教
  • 2015年04月 - 2016年09月 北海道大学大学院 農学研究院 博士研究員
  • 2013年04月 - 2015年03月 広島大学大学院 生物圏科学研究科 博士研究員
  • 2012年04月 - 2013年03月 広島大学大学院 生物圏科学研究科 特別研究員

学歴

  • 2009年04月 - 2012年03月   広島大学大学院   生物圏科学研究科   環境循環系制御学専攻
  • 2007年04月 - 2009年03月   北海道大学大学院   農学院   共生基盤学専攻
  • 2003年04月 - 2007年03月   北海道大学   農学部   生物機能化学科

受賞

  • 2022年09月 日本土壌肥料学会 学会奨励賞
     植物の土壌中難利用性リン獲得機構に関する研究 
    受賞者: 丸山 隼人

論文

  • Toshihiro Watanabe, Nozomi Imai, Syuntaro Hiradate, Hayato Maruyama, Jun Wasaki
    Journal of Plant Research 2024年11月11日
  • Masataka Suzuki, Katashi Kubo, Mayumi Hachinohe, Takashi Sato, Hirofumi Tsukada, Noriko Yamaguchi, Toshihiro Watanabe, Hayato Maruyama, Takuro Shinano
    Science of The Total Environment 167939  2023年11月 [査読有り][通常論文]
  • 山田 大綱, 田中 輝, 小濱 卓郎, 丸山 隼人, 田中 若奈, 西田 翔, 佐々木 孝行, 和崎 淳
    日本土壌肥料学会講演要旨集 69 45 - 45 一般社団法人 日本土壌肥料学会 2023年09月04日
  • Tatsuhiro Ezawa, Alessandro Silvestri, Hayato Maruyama, Keitaro Tawaraya, Mei Suzuki, Yu Duan, Massimo Turina, Luisa Lanfranco
    mBio 2023年05月10日 
    Mitoviruses in the family Mitoviridae are the mitochondria-replicating “naked RNA viruses” with genomes encoding only the replicase RNA-dependent RNA polymerase (RdRp) and prevalent across fungi, plants, and invertebrates. Arbuscular mycorrhizal fungi in the subphylum Glomeromycotina are obligate plant symbionts that deliver water and nutrients to the host. We discovered distinct mitoviruses in glomeromycotinian fungi, namely “large duamitovirus,” encoding unusually large RdRp with a unique N-terminal motif that is endogenized in some host genomes. More than 400 viral sequences similar to the large duamitoviruses are present in metatranscriptome databases. They are globally distributed in soil ecosystems, consistent with the cosmopolitan distribution of glomeromycotinian fungi, and formed the most basal clade of the Mitoviridae in phylogenetic analysis. Given that glomeromycotinian fungi are the only confirmed hosts of these viruses, we propose the hypothesis that large duamitoviruses are the most ancestral lineage of the Mitoviridae that have been maintained exclusively in glomeromycotinian fungi.
  • Muhamad Syaifudin, Masataka Suzuki, Hayato Maruyama, Katashi Kubo, Toshihiro Watanabe, Takuro Shinano
    Soil Science and Plant Nutrition 2023年03月04日 [査読有り]
  • Soichiro Honda, Yumiko Yamazaki, Takumi Mukada, Weiguo Cheng, Masaru Chuba, Yozo Okazaki, Kazuki Saito, Akira Oikawa, Hayato Maruyama, Jun Wasaki, Tadao Wagatsuma, Keitaro Tawaraya
    Plants 2023年03月
  • Mayumi Hachinohe, Hideshi Fujiwara, Takuro Shinano, Hayato Maruyama, Katashi Kubo, Takashi Saito
    Journal of Food Protection 86 3 100060 - 100060 2023年03月
  • Chengming Zhang, Chaoqun Zhang, Takayuki Azuma, Hayato Maruyama, Takuro Shinano, Toshihiro Watanabe
    Annals of Botany 2023年01月20日 
    Abstract Background and Aims The abundance or decline of fern populations in response to environmental change has been found to be largely dependent on specific physiological properties that distinguish ferns from angiosperms. Many studies have focused on water use efficiency and stomatal behaviours, but the effects of nutrition acquirement and utilization strategies on niche competition between ferns and flowering plants are rarely reported. Methods We collected 34 ferns and 42 angiosperms from the Botanic Garden of Hokkaido University for nitrogen (N), sulphur (S), NO3− and SO42− analysis. We then used a hydroponic system to compare the different N and S utilization strategies between ferns and angiosperms under N deficiency conditions. Key Results Ferns had a significantly higher NO3−-N concentration and NO3−-N/N ratio than angiosperms, although the total N concentration in ferns was remarkably lower than that in the angiosperms. Meanwhile, a positive correlation between N and S was found, indicating that nutrient concentration is involved in assimilation. Pteris cretica, a fern species subjected to further study, maintained a slow growth rate and lower N requirement in response to low N stress, while both the biomass and N concentration in wheat (Triticum aestivum) responded quickly to N deficiency conditions. Conclusions The different nutritional strategies employed by ferns and angiosperms depended mainly on the effects of phylogenetic and evolutionary diversity. Ferns tend to adopt an opportunistic strategy of limiting growth rate to reduce N demand and store more pooled nitrate, whereas angiosperms probably utilize N nutrition to ensure as much development as possible under low N stress. Identifying the effects of mineral nutrition on the evolutionary results of ecological competition between plant species remains a challenge.
  • Takuro Shinano, Satoshi Asaeda, Saeko Yashiro, Takashi Saito, Hayato Maruyama, Tomoaki Nemoto, Mayumi Hachinohe
    Soil Science and Plant Nutrition 2023年01月02日
  • Masataka Suzuki, Tetsuya Eguchi, Kazuki Azuma, Atsushi Nakao, Katashi Kubo, Shigeto Fujimura, Muhamad Syaifudin, Hayato Maruyama, Toshihiro Watanabe, Takuro Shinano
    The Science of the total environment 857 Pt 1 159208 - 159208 2022年10月05日 
    To mitigate radioactive cesium from soil to plant, increasing and maintaining the exchangeable potassium (ExK) level during growth is widely accepted after Tokyo Electric Company's Fukushima Dai-ichi Nuclear Plant accident in Japan. This is because the antagonistic relationship between soil solution K and 134Cs + 137Cs (RCs) concentrations changes the transfer factor (TF: designated as the ratio of radioactivity of plant organ to soil) of RCs. As the relationship between ExK and TF depends on the soil types, crop species, and other environmental factors, the required amount of ExK should be set to a safe side. Eleven years after the accident, as the activity of 134Cs was almost negligible, 137Cs became the main RCs in most of the agricultural fields in Fukushima Prefecture. We propose a new indicator, the concentration ratio of plant 137Cs to soil exchangeable 137Cs (Ex137Cs), instead of TF, which showed a better correlation with ExK even among soils with different properties (or mineralogy).
  • 坂口 文香, 丸山 隼人, 佐々木 孝行, 西田 翔, 和崎 淳, 信濃 卓郎, 渡部 敏裕
    日本土壌肥料学会講演要旨集 68 59 - 59 一般社団法人 日本土壌肥料学会 2022年09月05日
  • 荒川 竜太, 鳥山 星呂, アクリッシュ 穂波, 渡部 敏裕, 信濃 卓郎, 丸山 隼人
    日本土壌肥料学会講演要旨集 68 62 - 62 一般社団法人 日本土壌肥料学会 2022年09月05日
  • Ayane Kan, Hayato Maruyama, Nao Aoyama, Jun Wasaki, Yoshiko Tateishi, Toshihiro Watanabe, Takuro Shinano
    Soil Science and Plant Nutrition 2022年07月27日 
    Phosphorus (P) is an essential element for crop production; however, availability tends to be low due to slow diffusion and high fixation in soils. To cope with phosphate deficiency, white lupines (Lupinus albus L.) form unique root structures called cluster roots. The objective of this study was to elucidate detailed spatial differences of the mechanisms under low-P condition in the root system using rhizoboxes. We cultivated plants in rhizoboxes with P-deficient soil for 33 days. We then harvested roots and the adjacent soil from 128 compartments by dividing 2 × 2 cm squares in the rhizoboxes. We investigated relative expression levels of several genes that encode proteins assumed to be involved in P solubilization or translocation. Additionally, we analyzed fractionated P, soluble metal cations (Fe, Al, and Mn), and enzyme activities in the soil of each compartment. We observed a significant positive correlation between one of the MATE (multidrug and toxic compound extrusion/detoxification) genes, LaMATE6, and soluble metal cations, suggesting the secretion of citric acid into the rhizosphere via MATE proteins increased soluble metal cation concentrations. Furthermore, we demonstrated that roots in the same developmental stages were likely to have different influences on the mobilization of fractionated P in the rhizosphere soil. Our findings highlight the importance of investigating the relationship between soil chemical properties and root functions at a high spatial resolution to elucidate the detailed mechanisms of P mobilization by plants.
  • Yusaku Sugimura, Ai Kawahara, Hayato Maruyama, Tatsuhiro Ezawa
    Frontiers in Plant Science 13 2022年07月04日 [査読有り]
     
    Plants have evolved diverse strategies for foraging, e.g., mycorrhizae, modification of root system architecture, and secretion of phosphatase. Despite extensive molecular/physiological studies on individual strategies under laboratory/greenhouse conditions, there is little information about how plants orchestrate these strategies in the field. We hypothesized that individual strategies are independently driven by corresponding genetic modules in response to deficiency/unbalance in nutrients. Roots colonized by mycorrhizal fungi, leaves, and root-zone soils were collected from 251 maize plants grown across the United States Corn Belt and Japan, which provided a large gradient of soil characteristics/agricultural practice and thus gene expression for foraging. RNA was extracted from the roots, sequenced, and subjected to gene coexpression network analysis. Nineteen genetic modules were defined and functionally characterized, from which three genetic modules, mycorrhiza formation, phosphate starvation response (PSR), and root development, were selected as those directly involved in foraging. The mycorrhizal module consists of genes responsible for mycorrhiza formation and was upregulated by both phosphorus and nitrogen deficiencies. The PSR module that consists of genes encoding phosphate transporter, secreted acid phosphatase, and enzymes involved in internal-phosphate recycling was regulated independent of the mycorrhizal module and strongly upregulated by phosphorus deficiency relative to nitrogen. The root development module that consists of regulatory genes for root development and cellulose biogenesis was upregulated by phosphorus and nitrogen enrichment. The expression of this module was negatively correlated with that of the mycorrhizal module, suggesting that root development is intrinsically an opposite strategy of mycorrhizae. Our approach provides new insights into understanding plant foraging strategies in complex environments at the molecular level.
  • Zhang Chengming, Nobuhiro Tanaka, Maria Stefanie Dwiyanti, Matthew Shenton, Hayato Maruyama, Takuro Shinano, Chu Qingnan, Xie Jun, Toshihiro Watanabe
    Rice Science 29 1 76 - 88 2022年01月
  • Toshihiro Watanabe, Ryoskuke Okada, Soyoka Tokunaga, Hayato Maruyama, Masaru Urayama, Takuro Shinano
    JOURNAL OF PLANT NUTRITION 45 9 1413 - 1424 2021年12月 
    In the present study, we conducted experiments using wheat to elucidate whether the increased accumulation of molybdenum in leaves under nitrogen deficiency is due to the plant's own metabolic response, and further to estimate the role of molybdenum in the nitrogen deficiency response. Even under different growth conditions such as soil culture, hydroponic culture, and aseptic culture, the nitrogen deficiency always increased the molybdenum accumulation in leaves of wheat. Because molybdenum supply to the soil enhanced the growth of wheat under nitrogen deficiency but did not increase plant nitrogen concentration, the increased molybdenum uptake might be involved in the adaptive mechanisms to nitrogen deficiency by increasing nitrogen use efficiency. Wheat under nitrogen deficiency accumulated more molybdenum in lower leaves. Moreover, the nitrogen concentration of wheat grown under nitrogen deficiency increased in the lower leaves and decreased in the upper leaves with the application of molybdenum. These results suggest that molybdenum might affect nitrogen translocation from older to younger leaves.
  • Atsuhide Takao, Jun Wasaki, Hisae Fujimoto, Hayato Maruyama, Takuro Shinano, Toshihiro Watanabe
    Soil Science and Plant Nutrition 1 - 8 2021年10月07日
  • Katashi Kubo, Hayato Maruyama, Hisae Fujimoto, Masataka Suzuki, Ayane Kan, Yusuke Unno, Takuro Shinano
    SOIL SCIENCE AND PLANT NUTRITION 67 6 707 - 715 2021年10月 
    Low transfer of radioactive cesium (radiocesium) from soil to grains of agricultural crops is desirable to ensure food safety for humans and animals. Although the transfer of radiocesium from soil to grains is higher in upland crops such as soybean (Glycine max L.) than in paddy rice (Oryza sativa L.), little information related to the specific difference in radiocesium accumulation among leguminous crops is available, or for the relation between soil conditions and radiocesium accumulation in leguminous crops. This study compared the pattern of radiocesium transfer from soil to grains between peanut (Arachis hypogaea L.) and soybean to elucidate the diversity of radiocesium accumulation in leguminous crops growing with different potassium levels in soil. Pot and field experiments with radiocesium-contaminated soil showed that the radiocesium concentration in grains was lower in peanut than in soybean plants. For peanut, radiocesium absorption was mainly from roots instead of gynophores and fruits formed in the soil. Radiocesium absorption and translocation from roots to shoots were lower in peanut than in soybean plants. Among shoot parts, radiocesium transfers from stems to leaves, shells, and grains were lower in peanut than in soybean plants. Potassium application to the soil decreased the radiocesium transfer from soil to grains in both crops. The radiocesium accumulation was lower in peanut than in soybean under both potassium applied and non-applied conditions. These results underscored the variation in radiocesium transfer from soil to grains in leguminous crops, and demonstrated that peanut plants had lower potential of radiocesium accumulation than soybean plants.
  • Toshihiro Watanabe, Ryota Tomizaki, Ryotaro Watanabe, Hayato Maruyama, Takuro Shinano, Masaru Urayama, Yoshinori Kanayama
    SCIENTIA HORTICULTURAE 287 2021年09月 
    Fruit blossom-end rot (BER) is a serious physiological disorder that can cause significant yield losses in tomato (Solanum lycopersicum). Although many studies have suggested that calcium (Ca) deficiency in tomato fruits is a major factor for BER, its onset mechanism has not been fully elucidated. Ionomics is a high-throughput elemental profiling of living organisms that can be applied to understand how differences in plant's physiological status involving inorganic elements. In this study, we examined ionomic differences between the tomato cultivar M82 and its introgression line IL8-3, which contains a short chromosome segment from its wild relative Solanum pennellii on chromosome 8 of M82, and has a low incidence of fruit BER. Among the essential elements, Ca showed marked different behavior between the two lines. IL8-3 showed preferential Ca partitioning to fruits compared with M82. The slow growth rate and high Ca concentration observed in IL8-3 fruit during the early growth stages may also be responsible for the low BER incidence in this line. Although Ca ions bind to cell wall pectin and membrane phospholipids, and contribute to cell structure stability, these components showed no significant differences between fruits of the two lines. The fruit ionome differed considerably between M82 and IL8-3, and was not affected by available Ca status in the field. The M82 fruit had higher concentrations of many elements such as magnesium, potassium, boron, and sulfur than did IL8-3, and this trend was also observed in rotten fruit. This suggests that the influence of the leaf (source), rather than the fruit (sink), could be involved in the onset mechanism of BER.
  • Genki Masuda, Hayato Maruyama, Hans Lambers, Jun Wasaki
    Plant and Soil 461 1-2 107 - 118 2021年04月01日 
    Aims: Cyperaceae are common on nutrient-poor soils, including in western Japan. We examined the ability of the native Cyperaceae from western Japan to form dauciform roots and assessed the potential resulting contribution to soil phosphorus (P) dynamics. Methods: We assessed dauciform roots for 28 native Cyperaceae. Shoots, roots (including dauciform roots), and bulk and rhizosheath soils of Carex lenta were collected in Seto Inland Sea district (western Japan). The number of dauciform roots, shoot P and nitrogen (N) concentration, and soil P status and fractions were analyzed. Results: We confirmed dauciform-root formation in many Cyperaceae including the genus Carex. The number of dauciform roots of C. lenta showed a negative correlation with total and available soil P concentrations and with shoot P concentration. In the rhizosheath of C. lenta with many mature dauciform roots, we found an increase of readily-available inorganic P (Pi) and a decrease of readily-soluble organic P and sparingly soluble Pi fractions, indicating that the dauciform roots contributed to the acquisition of poorly-available soil P. Conclusions: Our results show negative correlations of the number of dauciform roots with both soil and plant P status. Regosols with a low P availability are common in Seto Inland Sea district thus the formation of dauciform roots and their exudates induced by low P status are important for the distribution of C. lenta in this region.
  • Katashi Kubo, Hayato Maruyama, Hisae Fujimoto, Masataka Suzuki, Ayane Kan, Yusuke Unno, Takuro Shinano
    Soil Science and Plant Nutrition 55 4 341 - 345 2021年 
    Low transfer of radioactive cesium (radiocesium) from soil to grains of agricultural crops is desirable to ensure food safety for humans and animals. Although the transfer of radiocesium from soil to grains is higher in upland crops such as soybean (Glycine max L.) than in paddy rice (Oryza sativa L.), little information related to the specific difference in radiocesium accumulation among leguminous crops is available, or for the relation between soil conditions and radiocesium accumulation in leguminous crops. This study compared the pattern of radiocesium transfer from soil to grains between peanut (Arachis hypogaea L.) and soybean to elucidate the diversity of radiocesium accumulation in leguminous crops growing with different potassium levels in soil. Pot and field experiments with radiocesium-contaminated soil showed that the radiocesium concentration in grains was lower in peanut than in soybean plants. For peanut, radiocesium absorption was mainly from roots instead of gynophores and fruits formed in the soil. Radiocesium absorption and translocation from roots to shoots were lower in peanut than in soybean plants. Among shoot parts, radiocesium transfers from stems to leaves, shells, and grains were lower in peanut than in soybean plants. Potassium application to the soil decreased the radiocesium transfer from soil to grains in both crops. The radiocesium accumulation was lower in peanut than in soybean under both potassium applied and non-applied conditions. These results underscored the variation in radiocesium transfer from soil to grains in leguminous crops, and demonstrated that peanut plants had lower potential of radiocesium accumulation than soybean plants.
  • Ryota Arakawa, Hisae Fujimoto, Haruka Kameoka, Seiro Toriyama, Yoshihiro Yoshida, Toshihiro Watanabe, Hayato Maruyama
    HORTICULTURE JOURNAL 90 4 401 - 409 2021年 
    Blossom-end rot (BER) in paprika (Capsicum annuum L.), as in tomato fruits, is a physiological disorder caused by calcium (Ca) deficiency in fruits. While studies have revealed that excessive nitrogen and potassium fertilization and high temperatures affect Ca transport to fruits and induce BER, few studies have investigated the effects of other elemental concentrations in paprika fruit and their association with BER occurrence. This study aimed to investigate the relationship between the changes in the elemental composition and incidence of BER in paprika fruits grown at different potassium nitrate (KNO3) concentrations and different temperature conditions. Paprika plants were grown in rockwool blocks in a greenhouse at 25 degrees C and 30 degrees C for approximately four months and irrigated with liquid fertilizer and three different concentrations (0, 27.9, and 74.4 mM) of KNO3 were added. Subsequently, the total fresh weights of ripe paprika fruits and the incidence of BER were measured, and the elemental compositions in the pericarp of the first and last sampled fruits were analyzed. The total fresh weights significantly decreased and the incidence of BER increased with increasing KNO3 concentrations and temperature. The profiles of 11 mineral elements in the pericarps of paprika fruits revealed a significant positive or negative correlation between not only the concentration of Ca, but also that of several other elements including boron (which crosslinks pectin in the cell wall like Ca) and the incidence of BER. These results suggest that Ca deficiency may not be the only cause of BER occurrence, and that several elements may also be involved. The insights from this study will contribute to help predict the incidence of BER and stabilize crop production by improving fertilizer application and environmental control.
  • Yusaku Sugimura, Ai Kawahara, Hayato Maruyama, Tatsuhiro Ezawa
    bioRxiv 2020年09月03日 [査読無し][通常論文]
     
    AbstractPlants have evolved diverse strategies for the acquisition of the macro-nutrients phosphorus and nitrogen; e.g., mycorrhizal formation, root development, and secretion of chelators/hydrolases to liberate inorganic phosphate. Despite the extensive studies on the individual strategies, there is little information about how plants regulate these strategies in response to fluctuating environment. We approached this issue via profiling transcriptomes of plants grown in large environmental gradients. Roots, leaves, and root-zone soils of 251 maize plants were collected across the US Corn Belt and Japan. RNA was extracted from the roots and sequenced, and the leaves and soils were analyzed. Nineteen genetic modules were defined by weighted gene coexpression network analysis and functionally characterized according to gene ontology analysis, by which we found three modules that are directly involved in nutrient acquisition: mycorrhizal formation, phosphate-starvation response (PSR), and root development. Correlation analysis with soil and plant factors revealed that both phosphorus and nitrogen deficiencies upregulated the mycorrhizal module, whereas the PSR module was upregulated mainly by deficiency in phosphorus relative to nitrogen. Expression levels of the root development module were negatively correlated with those of the mycorrhizal module, suggesting that nutrient acquisition through the two pathways, mycorrhizas and roots, are opposite strategies that are employed under nutrient-deficient and -enriched conditions, respectively. The identification of the soil and plant factors that drive the modules has implications for sustainable agriculture; activation/optimization of the strategies is feasible via manipulating the factors. Overall, our study opens a new window for understanding plant response to complex environments.
  • 齋藤 百花, 西田 翔, 丸山 隼人, 俵谷 圭太郎, 和崎 淳
    日本土壌肥料学会講演要旨集 66 45 - 45 一般社団法人 日本土壌肥料学会 2020年09月01日
  • 藤本 久恵, 高雄 惇英, 丸山 隼人, 俵谷 圭太郎, 信濃 卓郎, 渡部 敏裕
    日本土壌肥料学会講演要旨集 66 197 - 197 一般社団法人 日本土壌肥料学会 2020年09月01日
  • Tatsuhiro Ezawa, Hayato Maruyama, Yusuke Kikuchi, Kaede Yokoyama, Chikara Masuta
    Methods in Molecular Biology 249 - 254 2020年 [査読有り][招待有り]
  • Chu Q, Sha Z, Maruyama H, Yang L, Pan G, Xue L, Watanabe T
    Plant, cell & environment 42 11 3027 - 3043 2019年11月 [査読有り][通常論文]
     
    To elucidate the mechanism of adaptation of leguminous plants to iron (Fe)-deficient environment, comprehensive analyses of soybean (Glycine max) plants (sampled at anthesis) were conducted under Fe-sufficient control and Fe-deficient treatment using metabolomic and physiological approach. Our results show that soybeans grown under Fe-deficient conditions showed lower nitrogen (N) fixation efficiency; however, ureides increased in different tissues, indicating potential N-feedback inhibition. N assimilation was inhibited as observed in the repressed amino acids biosynthesis and reduced proteins in roots and nodules. In Fe-deficient leaves, many amino acids increased, accompanied by the reduction of malate, fumarate, succinate, and α-ketoglutarate, which implies the N reprogramming was stimulated by the anaplerotic pathway. Accordingly, many organic acids increased in roots and nodules; however, enzymes involved in the related metabolic pathway (e.g., Krebs cycle) showed opposite activity between roots and nodules, indicative of different mechanisms. Sugars increased or maintained at constant level in different tissues under Fe deficiency, which probably relates to oxidative stress, cell wall damage, and feedback regulation. Increased ascorbate, nicotinate, raffinose, galactinol, and proline in different tissues possibly helped resist the oxidative stress induced by Fe deficiency. Overall, Fe deficiency induced the coordinated metabolic reprogramming in different tissues of symbiotic soybean plants.
  • Ryan MH, Kaur P, Nazeri NK, Clode PL, Keeble-Gagnère G, Doolette AL, Smernik RJ, Van Aken O, Nicol D, Maruyama H, Ezawa T, Lambers H, Millar AH, Appels R
    Plant, cell & environment 42 6 1987 - 2002 2019年06月 [査読有り][通常論文]
     
    Crops with improved uptake of fertilizer phosphorus (P) would reduce P losses and confer environmental benefits. We examined how P-sufficient 6-week-old soil-grown Trifolium subterraneum plants, and 2-week-old seedlings in solution culture, accumulated P in roots after inorganic P (Pi) addition. In contrast to our expectation that vacuoles would accumulate excess P, after 7 days, X-ray microanalysis showed that vacuolar [P] remained low (<12 mmol kg-1 ). However, in the plants after P addition, some cortex cells contained globular structures extraordinarily rich in P (often >3,000 mmol kg-1 ), potassium, magnesium, and sodium. Similar structures were evident in seedlings, both before and after P addition, with their [P] increasing threefold after P addition. Nuclear magnetic resonance (NMR) spectroscopy showed seedling roots accumulated Pi following P addition, and transmission electron microscopy (TEM) revealed large plastids. For seedlings, we demonstrated that roots differentially expressed genes after P addition using RNAseq mapped to the T. subterraneum reference genome assembly and transcriptome profiles. Among the most up-regulated genes after 4 hr was TSub_g9430.t1, which is similar to plastid envelope Pi transporters (PHT4;1, PHT4;4): expression of vacuolar Pi-transporter homologs did not change. We suggest that subcellular P accumulation in globular structures, which may include plastids, aids cytosolic Pi homeostasis under high-P availability.
  • Akyol TY, Niwa R, Hirakawa H, Maruyama H, Sato T, Suzuki T, Fukunaga A, Sato T, Yoshida S, Tawaraya K, Saito M, Ezawa T, Sato S
    Microbes and environments 34 1 23 - 32 2019年03月30日 [査読有り][通常論文]
     
    Arbuscular mycorrhizal (AM) fungi are important members of the root microbiome and may be used as biofertilizers for sustainable agriculture. To elucidate the impact of AM fungal inoculation on indigenous root microbial communities, we used high-throughput sequencing and an analytical pipeline providing fixed operational taxonomic units (OTUs) as an output to investigate the bacterial and fungal communities of roots treated with a commercial AM fungal inoculum in six agricultural fields. AM fungal inoculation significantly influenced the root microbial community structure in all fields. Inoculation changed the abundance of indigenous AM fungi and other fungal members in a field-dependent manner. Inoculation consistently enriched several bacterial OTUs by changing the abundance of indigenous bacteria and introducing new bacteria. Some inoculum-associated bacteria closely interacted with the introduced AM fungi, some of which belonged to the genera Burkholderia, Cellulomonas, Microbacterium, Sphingomonas, and Streptomyces and may be candidate mycorrhizospheric bacteria that contribute to the establishment and/or function of the introduced AM fungi. Inoculated AM fungi also co-occurred with several indigenous bacteria with putative beneficial traits, suggesting that inoculated AM fungi may recruit specific taxa to confer better plant performance. The bacterial families Methylobacteriaceae, Acetobacteraceae, Armatimonadaceae, and Alicyclobacillaceae were consistently reduced by the inoculation, possibly due to changes in the host plant status caused by the inoculum. To the best of our knowledge, this is the first large-scale study to investigate interactions between AM fungal inoculation and indigenous root microbial communities in agricultural fields.
  • Maruyama H, Sasaki T, Yamamoto Y, Wasaki J
    Plant & cell physiology 60 1 107 - 115 2019年01月01日 [査読有り][通常論文]
     
    Under phosphorus (P)-deficient conditions, organic acid secretion from roots plays an important role in P mobilization from insoluble P in the soil. In this study, we characterized AtALMT3, a homolog of the Arabidopsis thaliana aluminum-activated malate transporter family gene. Among the 14 AtALMT family genes, only AtALMT3 was significantly up-regulated in P-deficient roots. AtALMT3 promoter::β-glucuronidase is expressed in the epidermis in roots, especially in root hair cells. AtALMT3 protein was localized in the plasma membrane and in small vesicles. Fluorescence of AtALMT3::GFP was not observed on the vacuole membrane of protoplast after lysis, indicating that AtALMT3 localizes mainly in the plasma membrane. Compared with the wild-type (WT) line, malate exudation in the AtALMT3-knockdown line (atalmt3-1) and overexpression line (atalmt3-2) under P deficiency were, respectively, 37% and 126%. In contrast, no significant difference was found in citrate exudation among these lines. The complementation of the atalmt3-1 line with AtALMT3 recovered the malate exudation to the level of the WT. Taken together, these results suggest that AtALMT3 localized in root hair membranes is involved in malate efflux in response to P deficiency.
  • Sho Nishida, D. M.S.B. Dissanayaka, Soichiro Honda, Yoshiko Tateishi, Masaru Chuba, Hayato Maruyama, Keitaro Tawaraya, Jun Wasaki
    Soil Science and Plant Nutrition 64 3 278 - 281 2018年05月04日 [査読有り][通常論文]
     
    Phosphorus (P) is a major nutrient supporting rice productivity. Improving low-P tolerance of rice is expected to reduce dependence on P fertilizer, thereby reducing rice production costs and environmental impacts. This report describes the mapping of quantitative trait loci (QTL) associated with P deficiency tolerance in japonica rice. An F5 population derived from a cross of the low-P tolerant cultivar Akamai (Yamagata) and the sensitive cultivar Koshihikari was evaluated for shoot growth under low-P conditions. Then single nucleotide polymorphism (SNP) profiles of the low-P tolerant and sensitive bulks were compared on a genome-wide scale by QTL-Seq, a rapid QTL mapping method using next-generation sequencing technology. Results show a major QTL associated with low-P tolerance located on the long arm of chromosome 12. It has been named QTL for low-P tolerance 1 or qLPT1. SNPs were detected in 45 genes of qLPT1 region and the 5 genes were harboring synonymous SNPs, although none of them had been reported as involved in low-P tolerance. This result implies that the novel gene responsible for low-P tolerance exists in qLPT1. This study will contribute to the elucidation of mechanisms underlying low-P tolerance of Akamai and will facilitate the breeding of rice with low-P tolerance.
  • Tawaraya K, Honda S, Cheng W, Chuba M, Okazaki Y, Saito K, Oikawa A, Maruyama H, Wasaki J, Wagatsuma T
    Physiologia plantarum 2018年02月07日 [査読有り][通常論文]
     
    Recycling of phosphorus (P) from P-containing metabolites is an adaptive strategy of plants to overcome soil P deficiency. This study was aimed at demonstrating differences in lipid remodelling between low-P-tolerant and -sensitive rice cultivars using lipidome profiling. The rice cultivars Akamai (low-P-tolerant) and Koshihikari (low-P-sensitive) were grown in a culture solution with [2 mg l-1 (+P)] or without (-P) phosphate for 21 and 28 days after transplantation. Upper and lower leaves were collected. Lipids were extracted from the leaves and their composition was analysed by liquid chromatography/mass spectrometry (LC-MS). Phospholipids, namely phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and phosphatidylinositol (PI), lysophosphatidylcholine (lysoPC), diacylglycerol (DAG), triacylglycerol (TAG) and glycolipids, namely sulfoquinovosyl diacylglycerol (SQDG), digalactosyldiacylglycerol (DGDG), monogalactosyldiacylglycerol (MGDG) and 1,2-diacyl-3-O-alpha-glucuronosyl glycerol (GlcADG), were detected. GlcADG level was higher in both cultivars grown in -P than in +P and the increase was larger in Akamai than in Koshihikari. DGDG, MGDG and SQDG levels were higher in Akamai grown in -P than in +P and the increase was larger in the upper leaves than in the lower leaves. PC, PE, PG and PI levels were lower in both cultivars grown in -P than in +P and the decrease was larger in the lower leaves than in the upper leaves and in Akamai than in Koshihikari. Akamai catabolised more phospholipids in older leaves and synthesised glycolipids in younger leaves. These results suggested that extensive phospholipid replacement with non-phosphorus glycolipids is a mechanism underlying low-P-tolerance in rice cultivars.
  • Tadao Wagatsuma, Eriko Maejima, Toshihiro Watanabe, Tomonobu Toyomasu, Masaharu Kuroda, Toshiya Muranaka, Kiyoshi Ohyama, Akifumi Ishikawa, Masami Usui, Shahadat Hossain Khan, Hayato Maruyama, Keitaro Tawaraya, Yuriko Kobayashi, Hiroyuki Koyama
    Journal of experimental botany 69 3 567 - 577 2018年01月23日 [査読有り][通常論文]
     
    Aluminum-sensitive rice (Oryza sativa L.) cultivars showed increased Al tolerance under dark conditions, because less Al accumulated in the root tips (1 cm) under dark than under light conditions. Under dark conditions, the root tip concentration of total sterols, which generally reduce plasma membrane permeabilization, was higher in the most Al-sensitive japonica cultivar, Koshihikari (Ko), than in the most Al-tolerant cultivar, Rikuu-132 (R132), but the phospholipid content did not differ between the two. The Al treatment increased the proportion of stigmasterol (which has no ability to reduce membrane permeabilization) out of total sterols similarly in both cultivars under light conditions, but it decreased more in Ko under dark conditions. The carotenoid content in the root tip of Al-treated Ko was significantly lower under dark than under light conditions, indicating that isopentenyl diphosphate transport from the cytosol to plastids was decreased under dark conditions. HMG2 and HMG3 (encoding the key sterol biosynthetic enzyme 3-hydroxy-3-methylglutaryl CoA reductase) transcript levels in the root tips were enhanced under dark conditions. We suggest that the following mechanisms contribute to the increase in Al tolerance under dark conditions: inhibition of stigmasterol formation to retain membrane integrity; greater partitioning of isopentenyl diphosphate for sterol biosynthesis; and enhanced expression of HMGs to increase sterol biosynthesis.
  • D. M. S. B. Dissanayaka, Hayato Maruyama, Sho Nishida, Keitaro Tawaraya, Jun Wasaki
    PLANT AND SOIL 414 1-2 327 - 338 2017年05月 [査読有り][通常論文]
     
    Aims Phosphorus (P) acquisition through extensive root growth and P allocation to different plant organs through efficient remobilization are important for acclimation of crop plants to P-limited environments. This study elucidated changes in rice root growth and leaf P-remobilization and their influence on grain yield under P deficiency. Methods Two pot experiments were conducted with (P100) and without (P0) inorganic P supply using two Japanese rice cultivars: Akamai (Yamagata) and Koshihikari. Multiple harvests were made until the panicle initiation stage. Root and shoot growth response, P acquisition, and temporal leaf P-remobilization efficiency were measured. A separate experiment ascertained the final yield and grain P status. Results The Akamai rice cultivar showed enhanced root growth and more acquired soil P. The Akamai root dry weight was 66% greater than that of Koshihikari under P0. Confronting P deficiency, Akamai remobilized some P from its lower mature leaves to upper younger leaves starting from early growth. The remobilized P fraction increased to 72% at panicle initiation under P0. Under P0, Akamai exhibited two-fold higher leaf P-remobilization efficiency than under P100. Conclusions Enhanced root growth that facilitates acquisition of more soil P through better soil exploration coupled with efficient leaf P remobilization from the early growth stage improves adaptation of Akamai rice cultivar to P-limited environments. Nevertheless, P-starvation responses did not facilitate higher grain yields in P-limited conditions.
  • 丸山隼人, 和崎淳
    化学と生物 55 3 189‐195  2017年02月20日 [査読無し][通常論文]
  • Hayato Maruyama, Jun Wasaki
    Plant Macronutrient Use Efficiency: Molecular and Genomic Perspectives in Crop Plants 323 - 338 2017年01月01日 [査読有り][通常論文]
     
    Phosphorus (P) is easily fixed in soils, forming unavailable forms, such as insoluble P and organic P. Plants frequently face P deficiency because of its low mobility in soil. Many strategies to adapt to P-deficient conditions have been developed in plants, but they can be categorized as two major strategies: (1) efficient use of sparingly available P by increase root exudation, including organic acids and phosphatases, by increase expression of phosphate transporter, and by modification of root architecture and (2) improvement of internal P use efficiency by alteration of carbon metabolisms and by lipid remodeling. The strategies are regulated by a complex signaling network. This chapter presents an overview of the strategies and past trials to improve P use efficiency by transformation of certain genes involved in low-P stress response including future perspectives.
  • 和崎淳, 丸山隼人, 俵谷圭太郎
    日本土壌肥料学雑誌 86 3 213 - 218 一般社団法人 日本土壌肥料学会 2015年06月05日 [査読無し][通常論文]
  • Dissanayaka Mudiyanselage Samantha Bandara Dissanayaka, Hayato Maruyama, Genki Masuda, Jun Wasaki
    PLANT AND SOIL 390 1-2 223 - 236 2015年05月 [査読有り][通常論文]
     
    This study of a maize-white lupin model cropping system was conducted to investigate the effects of rhizosphere-sharing of white lupin, a P-efficient plant, on growth and P accumulation of maize under different P rates and forms in two contrasting soils. With Regosol and Andosol, a 42-day pot experiment was conducted for 0P (no P addition), 50Pi, 100Pi (50 and 100 mg P kg(-1) soil by NaHPO(4)a <...2H(2)O respectively), and 100Po (100 mg P kg(-1) soil by phytate). Plant growth, P uptake, rhizosphere pH, and different P fractions were investigated. Complementary effects of intercropping for maize were observed in Regosol, but not in Andosol. Total P uptake by intercropped maize in 0P, 50Pi, and 100Po was elevated by 46, 37, and 65 %, respectively, compared to when it was grown as a monoculture. White lupin mobilized P from sparingly soluble forms. Thereby, maize plant enhanced its P accumulation as a result of access to these two fractions in mixed culture in Regosol, where strong root intermingling occurred among intercropped plants. Results suggest that the P mobilization strategy of white lupin from sparingly soluble P pools in soil can enhance the P acquisition efficiency of coexisting maize with P facilitation in this intercropping occurring in the direction of white lupin to maize. Achieving enhanced growth and P uptake by P-inefficient species in intercropping with white lupin is dependent on the type of soil in which those plants are grown.
  • 山内大輝, 丸山隼人, 内田慎治, 向井誠二, 坪田博美, 和崎淳
    植物研究雑誌 90 2 103 - 108 ツムラ 2015年04月20日 [査読無し][通常論文]
  • 和崎淳, 和崎淳, 丸山隼人
    地球環境 20 1 97 - 102 国際環境研究協会 2015年 [査読無し][通常論文]
  • Hayato Maruyama, Takuya Yamamura, Yohei Kaneko, Hirokazu Matsui, Toshihiro Watanabe, Takuro Shinano, Mitsuru Osaki, Jun Wasaki
    SOIL SCIENCE AND PLANT NUTRITION 58 1 41 - 51 2012年 [査読有り][通常論文]
     
    This study evaluated the effects of exogenous LASAP2 for acid phosphatase (APase) and LASAP3 for phytase of white lupin (Lupinus albus L.) on phosphorus (P) accumulation from organic P in soils. The potential for LASAP2-overexpressing tobacco (Nicotiana tabacum L.) to increase organic P in soil was examined in our previous study. However, LASAP2 has low specificity for phytate, the predominant form of unavailable P in the brown lowland soil. For the present study, we isolated the full length of LASAP3 cDNA and introduced it into tobacco plants using Agrobacterium-mediated transformation. Transgenic tobacco plants were grown in two different soils (Andosols and Regosols; high and low P-adsorption capacity, respectively) supplemented with either inorganic phosphate (+Pi) or phytate (Po) as the sole P source, or control conditions that lacked phosphorus (No P). Dry matter production and P content of the transgenic line was higher than that of wild type in all treatments. The ratio of P accumulation increase by exogenous enzymes was found to be dependent on the P treatment and soil type. In all lines, the increase in +Po was less than that in +Pi, but higher than in No P. The P uptake ability of plants in Regosols was higher than in Andosols for all treatments, suggesting that the P utilization efficiency of both Pi and Po is dependent on the solubility. In no soil type or P treatment was a significant difference found between LASAP2- and LASAP3-overexpressing lines. These results demonstrate that introducing an APase and phytase gene such as LASAP2 and LASAP3 into tobacco by genetic transformation is a promising strategy for improving P mobilization in soil, although the bottleneck for mobilization of phytate-P is not the specificity of the enzyme but its solubility in soils.
  • Jun Wasaki, Hayato Maruyama, Miho Tanaka, Takuya Yamamura, Hiraki Dateki, Takuro Shinano, Susumu Ito, Mitsuru Osaki
    SOIL SCIENCE AND PLANT NUTRITION 55 1 107 - 113 2009年02月 [査読有り][通常論文]
     
    Secretion of acid phosphatase (APase) from the roots to take up phosphorus (P) is a well-known strategy of plants under P-deficient conditions. White lupin, which shows vigorous growth in low-P soils, is noted for its ability to secrete APase under P-deficient conditions. The APase secreted by white lupin roots is stable in soil solution and shows low substrate specificity, suggesting that genetic modification of plants using the APase gene LASAP2 might improve their ability to use organic P. The objective of the present study was to evaluate the potential of LASAP2 transgenic plants to increase organic P utilization. Dry matter production and P accumulation were higher in LASAP2 transgenic tobacco plants grown in gel media containing soluble phytate as the sole P source than in wild-type tobacco plants. Phosphorus uptake by the transgenic plants also increased in soil culture conditions. LASAP2 was apparently more effective in the liberation of organic P, including phytate, in the soil than the native tobacco APase. Thus, the enzymatic stability of LASAP2 in the soil appears to be an important factor for P acquisition.
  • Jun Wasaki, Hayato Maruyama, Miho Tanaka, Takuya Yamamura, Hiraki Dateki, Takuro Shinano, Susumu Ito, Mitsuru Osaki
    SOIL SCIENCE AND PLANT NUTRITION 55 1 107 - 113 2009年02月 [査読有り][通常論文]
     
    Secretion of acid phosphatase (APase) from the roots to take up phosphorus (P) is a well-known strategy of plants under P-deficient conditions. White lupin, which shows vigorous growth in low-P soils, is noted for its ability to secrete APase under P-deficient conditions. The APase secreted by white lupin roots is stable in soil solution and shows low substrate specificity, suggesting that genetic modification of plants using the APase gene LASAP2 might improve their ability to use organic P. The objective of the present study was to evaluate the potential of LASAP2 transgenic plants to increase organic P utilization. Dry matter production and P accumulation were higher in LASAP2 transgenic tobacco plants grown in gel media containing soluble phytate as the sole P source than in wild-type tobacco plants. Phosphorus uptake by the transgenic plants also increased in soil culture conditions. LASAP2 was apparently more effective in the liberation of organic P, including phytate, in the soil than the native tobacco APase. Thus, the enzymatic stability of LASAP2 in the soil appears to be an important factor for P acquisition.
  • Jun Wasaki, Soichi Kojima, Hayato Maruyama, Susan Haase, Mitsuru Osaki, Ellen Kandeler
    SOIL SCIENCE AND PLANT NUTRITION 54 1 95 - 102 2008年02月 [査読有り][通常論文]
     
    Acid phosphatase (APase) produced by the cluster roots of white lupin (Lupinus albus L.) plays an important role in inorganic phosphate (Pi) acquisition. Although the importance of cluster roots in Pi acquisition is well known, information on the distribution of APase within tissues of normal and cluster roots is lacking. Isoelectric focusing of APase isoforms as well as histochemical localization and visualization of APase were used to clarify the importance of secretory APase for P nutrition of white lupin grown under P deficiency. Isoelectric focusing revealed that both the secretory type and other major APase isoforms probably involved in P translocation were inducible. The major activity in the rhizosphere soil of cluster roots and roots grown under hydroponic conditions corresponded to LASAP2, a previously purified APase secreted from white lupin roots. Histochemical localization using enzyme-labeled fluorescence (ELF)-97 phosphate as a substrate was applied to rhizosphere samples. This substrate provides fluorescent precipitates after hydrolysis by phosphatase. Strong APase activity in the epidermal tissues of normal roots and cluster rootlets and in root hairs of cluster rootlets under P deficiency was detected. These results support the hypothesis that APase activities in the rhizosphere liberate Pi and supply it to white lupin plants grown under P-deficient conditions.
  • Hayato Maruyama, Miho Tanaka, Takuya Yamamura, Takuro Shinano, Susumu Ito, Jun Wasaki, Mitsufu Osaki
    PLANT AND CELL PHYSIOLOGY 48 S30 - S30 2007年 [査読有り][通常論文]

MISC

所属学協会

  • 日本植物生理学会   日本土壌肥料学会   日本育種学会   

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2023年04月 -2027年03月 
    代表者 : 渡部 敏裕, 和崎 淳, 平舘 俊太郎, 佐野 雄三, 丸山 隼人, 東 隆行
  • 日本学術振興会：科学研究費助成事業 基盤研究(A)
    研究期間 : 2021年04月 -2025年03月 
    代表者 : 和崎 淳, 坪田 博美, 丸山 隼人, 西田 翔, 渡部 敏裕, 佐々木 孝行, 俵谷 圭太郎, 廣田 隆一
     
    リン酸質肥料は作物生産に必須であるが、資源は涸渇に瀕しており、持続的な作物生産にはその問題の解決が必要である。低リン耐性を有する一部の植物は、クラスター根とよばれる小根が密集した根を形成する能力がある。このクラスター根は、根の表面積を増やし、難利用性リンの吸収を強化して適応するために形成されると考えられているが、その形成能と難利用性リンの供給能の詳細は未解明である。本研究ではシステムズ生物学アプローチ解析によるクラスター根の形態形成イベントの制御、爆発的な根分泌の誘導による難利用性リンからの供給能の解明に取り組む。 これまでに、クラスター根形成種であるシロバナルーピンおよびHakea laurinaのRNA-seqデータなどを元にして複数の有機酸トランスポーター候補の同定に成功した。これらの候補遺伝子の発現量を調査したところ、低リン条件のクラスター根で顕著な発現誘導が確認された。また、シロバナルーピンのRNA-seqデータからクラスター根の発達へのエチレンの寄与が示唆されたことから、エチレン前駆体であるACCおよびエチレン合成阻害剤であるCo2+イオンを添加してその影響を評価した。その結果、エチレンはクラスター根を構成する小根の伸長停止に寄与するとともに、リン欠乏への発現応答にも関与していることが示唆された。 新規なクラスター根形成種の探索を行うため、根のメタバーコーディングライブラリー作成のためのサンプル採集を進めた。クラスター根圏土壌細菌群集のメタバーコーディングを行うため、根圏土壌を採取し、アンプリコンシーケンスの準備を進めた。シロバナルーピンの根箱栽培を実施し、クラスター根におけるリン可溶化に関わる遺伝子発現および土壌中のリン形態を調査した結果、クラスター根の発達段階だけでなく根が形成された位置による違いが認められ、局所的に異なる機能を持つことが明らかとなった。
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2020年04月 -2023年03月 
    代表者 : 丸山 隼人
     
    アーバスキュラー菌根(AM)菌と共生した植物（菌根形成植物）は植物自身による直接経路とAM菌を介した菌根経路からリン酸を吸収するが、その経路の制御およびリン獲得への寄与に関しては不明である。本研究では、菌根共生機能を活用したリン資源の効率的な利用に資する分子基盤を明らかにすることを目指す。本年度は、昨年度実施した2種類のAM菌Rhizophagus irregularis(Ri区), Rhizophagus clarus(Rc区)を接種したミナトカモジグサにおける根と内生菌糸のトランスクリプトームを解析し、生育期間中における植物体とAM菌の相互作用を遺伝子発現レベルで調査した。根の遺伝子発現量に対し共発現ネットワークを実施したところ、AM菌感染に関わる遺伝子群(AMモジュール)を同定した。これらモジュールの中には、菌根形成特異的なリン酸輸送体や脂質合成・輸送関連遺伝子が含まれていた。AMモジュール中の遺伝子プロファイルはRc区とRi区でその多くが共通していたが、Alkaloid合成やCaroten合成に関わる遺伝子が特異的にRc区に多く含まれており、AM菌感染に関わる植物ホルモンの制御が異なることが示唆された。 次に、根を２つの区画に分けてミナトカモジグサを栽培し、片方の区画にAM菌 R. irregularisを３段階(0, 100, 300 spores)で接種した。20日, 27日後にサンプリングを行い、地上部および根を収穫した。20日後には接種の有無による差は確認できなかったが、27日後にはバイオマスとリン濃度が300spores接種区で顕著に改善された。今後は感染個体の非感染根と非感染個体の非感染根のトランスクリプトーム比較およびそれぞれの区画における土壌リン可溶化に関わる形質評価を実施し、菌根形成が直接経路のリン獲得能に与える影響を評価する予定である。
  • 日本学術振興会：科学研究費助成事業 基盤研究(A)
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 信濃 卓郎, 和崎 淳, 海野 佑介, 丸山 隼人, 齋藤 隆, 尹 永根, 渡部 敏裕, 俵谷 圭太郎, 若林 正吉
     
    短半減期の放射性同位元素(11C)を地上部にCO2として地上部に同化させ、この同化産物の土壌への分泌パターンを解析する取り組みを進めた。試験では植物の根の生育状況を改善するために根箱の改良にまず取り組み、水耕栽培にてある程度植物体を成長させ、適切な根系を発達させた後に、メンブレンで根の侵入を抑制した根箱に挟み込む手法を導入する事で、根とその周辺の土壌を分けることに成功した。 このように根と土壌の間に根の移動を遮る膜を設置することで、根への化合物の移動と、根圏への分泌物を区分する技術を、豆科作物のルーピンに適用した。得られた土壌の物理性（粘土鉱物組成）、化学性（各種元素の溶解度の変化）、生物性（微生物群衆構造）の解析を進めている。根分泌液に含まれる代謝産物を土壌溶液から包括的に解析する目的の前段階として植物がカリウム栄養に応じてどのように分泌化合物の変動を示すのかについての解析をメタボローム解析を用いて進めた。また、実際の土壌御輸液を解析するためにキャピラリー電気泳動質量分析装置を利用する方向で取り組んでいるが、特にカチオンの代謝産物を精度よく解析するための徐塩の条件件を進めた。 さらに、供試するルーピンの放射性セシウム吸収特性を晶完備するためbに福島県内の放射性セシウムによって汚染された圃場において栽培試験を行った。その結果、ルーピンは従来知られているいずれの作物に比べても著しく高い放射性セシウム吸収能を有する事が明らかになった。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 和崎 淳, 坪田 博美, 丸山 隼人, 西田 翔, 渡部 敏裕, 佐々木 孝行, 俵谷 圭太郎
     
    リン酸質肥料の原料は涸渇に瀕しており、持続的な食料生産のためには低リン環境で生育可能な「低リン超耐性植物」の耐性を理解し、そのしくみを活用する必要がある。マメ科ルピナス属やヤマモガシ科等の低リン超耐性植物は、クラスター根を形成して適応するが、低リン環境でのクラスター根形成や有機酸分泌など機能発現のしくみの多くは未解明である。本研究はこれを明らかにするとともに、低リン超耐性植物の農業利用の可能性および生態学的機能を追究することを目的とする。今年度は主に以下の研究を実施した。 シロバナルーピン3品種およびクラスター根を形成しないアオバナルーピンを用いてリンを与えた+P区、与えない-P区で水耕栽培を行い、継時的に形質を評価した。地上部の葉における再転流効率がシロバナルーピンの3品種で高いこと、根分泌物中のホスファターゼ活性およびクエン酸の分泌能はアオバナルーピンおよびシロバナルーピンの品種Luxorで高いことが示された。リンを与えずに土耕栽培したところ、シロバナルーピンのクラスター根圏で難利用性リンの減少が大きく、アオバナルーピンの根圏で小さかった。 アフリカツメガエル卵母細胞の遺伝子発現系を用いて、リン酸欠乏に応答するMATEタイプ蛋白質を発現させて、クエン酸放出などの輸送活性を電気生理学的手法により解析したところ、N-GFP-LaMATEの方がC-GFPよりも発現がみられ、卵母細胞の細胞膜に局在することが示された。 ヤマモガシのクラスター根圏におけるリンの動態を調査したところ、根圏ではpHが低下し、土壌中のリンが非根圏と比較して半分程度まで低下した。特に難溶性有機態リンの減少が顕著であった。さらに、砂耕栽培において個体あたりの有機酸分泌量はクラスター根の形成数と正の相関があることが示された。 以上の結果より、クラスター根が実際の土壌中からのリン吸収に寄与していることが強く支持された。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2015年04月 -2018年03月 
    代表者 : 我妻 忠雄, 和崎 淳, 小林 佑理子, 渡部 敏裕, 俵谷 圭太郎, 丸山 隼人, 小山 博之, 黒田 昌治, 岡咲 洋三
     
    Indicaは、Alによる膜脂質層内での隙間形成による膜透過性増大を阻止できないstigmasterolが著しく多いことが解った。pah1pah2シロイヌナズナはAl耐性が弱く、膜脂質成分がwild-typeとは異なった。HMGPAHはCd耐性が向上した。HMGイネはAl耐性が向上する傾向だったが、さらに検討中である。PAHはイネのリンリサイクリングを促進し低リン耐性強化に貢献し、下位葉でのPL分解能の高さが、イネの低リン耐性を向上させることも解った。以上により、膜脂質層のsterolを増やしPLを減らすことが、イオンストレスマルチ耐性に重要であると示唆された。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 江澤 辰広, 増田 税, 斎藤 勝晴, 丸山 隼人, 河原 愛, 菊池 裕介, 横山 楓
     
    アーバスキュラー菌根菌 (AM菌) は約80%の陸上植物と共生関係を構築し、宿主から炭素源を受けとる代わりに、土壌中のリン酸を供給する。この共生的リン酸供給のプロセスにおいて、共生菌側の分子機構は未だほとんどわかってない。本研究では、世界で初めて植物ウイルスを用いてAM菌の遺伝子をノックダウンする方法を確立し、AM菌水輸送体が菌糸内に植物方向への水の流れを作り出してリン酸を輸送していることを証明した。また、AM菌から植物へのリン酸の放出に関わる排出型リン酸輸送体遺伝子を特定し、同様にウイルスを用いたノックダウン実験により、この輸送体を介してAM菌は植物にリン酸を受け渡していることを示した。

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