研究者詳細 - 仲田（狩野）　麻奈

Root and shoot responses of upland New Rice for Africa varieties to fluctuating soil moisture conditions as affected by different levels of nitrogen fertilization

Menge, DM; Kano-Nakata, M; Yamauchi, A; Suralta, RR; Makihara, D

JOURNAL OF AGRONOMY AND CROP SCIENCE 206 巻 ( 3 ) 頁： 322 - 337 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Agronomy and Crop Science

Drought cycling and soil re-watering trends due to intermittent rainfall patterns are key stress factors that influence rice growth and yield under upland cultivation conditions. However, upland rice adaptation responses to fluctuating soil moisture conditions remain poorly understood. This study investigated root and shoot responses of upland New Rice for Africa (NERICA) varieties to episodic drought and re-watering during growth. We examined root and shoot growth of NERICA 1 and NERICA 4 compared with those of IR72, an improved lowland variety, and Dular, a traditional drought-tolerant variety, in terms of soil moisture fluctuations with different levels of nitrogen fertilization under field conditions that impeded deep root development. During soil moisture fluctuation, all varieties reduced shoot dry weight compared with well-watered plants, regardless of nitrogen fertilization levels. However, total root length for the three upland varieties was enhanced by soil moisture fluctuations at moderate and high nitrogen fertilization, while that of the lowland variety was reduced. Comparing root development during water fluctuations revealed that NERICA 1 had a greater root system than NERICA 4, which was attributed to lateral root development. Furthermore, we found that NERICA varieties increase lateral root mass during soil desiccation under adequate nitrogen fertilization, while Dular and IR72 reduced their root growth rate during drought and increased it after re-watering. Both root growth patterns developed, from around maximum tillering to heading. The analysis of regression between root elongation and shoot growth with fluctuating soil moisture indicated that an enhanced root system during drought, on adequate nitrogen fertilization, can contribute to shoot growth when sufficient water becomes available, specifically around the maximum tillering to the heading growth stage of rice.

DOI： 10.1111/jac.12390

Morphological and histological differences among three types of component roots and their differential contribution to water uptake in the rice root system

Enhanced Root System Development Responses of a Newly Identified Mutation Gene Promoting Lateral Root Development to Various Nitrogen Conditions in Rice. 査読有り国際共著

Lucob-Agustin, N., Hasegawa, T., Jinno, K., Suralta, R. R., Niones, J. M., Kano-Nakata, M., Yamauchi, A. and Inukai, Y.

Journal of International Cooperation for Agricultural Development 18 巻頁： 48 - 55 2020年3月

Watanabe, Y; Kabuki, T; Kakehashi, T; Kano-Nakata, M; Mitsuya, S; Yamauchi, A

PLANT PRODUCTION SCIENCE 23 巻 ( 2 ) 頁： 191 - 201 2020年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plant Production Science

The rice root system consists of three types of roots; main root, L-type and S-type lateral root (LR). These component roots are morphologically and histologically different, which is termed as heterorhizy. Root system hydraulic architecture is related to the unique features of component roots. We hypothesized that each component root contributes in different degrees to water uptake of the whole root system. Rice varieties IRAT 109 and Taichung 65 were grown in pots filled with soil under continuous waterlogged (CWL) and drought (CD) conditions until two weeks after heading. Morphology and histological structures of roots, which may regulate radial water movement, were compared among the three component roots. Moreover, hydraulic conductivity (Lpr) of the root system, which represents the water uptake ability, were measured with a pressure chamber. Based on a model that Lpr of the whole root system is a product of Lpr of each of the component roots and their surface areas, we found that the differences in Lpr between the two varieties and the plants grown under different soil water conditions for any of the component roots did not support the corresponding differences in the measured Lpr of the whole root system. In contrast, a significant and positive correlation was found between Lpr of the whole root system and the percentage of surface area of S-type LR but not for the other component roots. These results indicate S-type LR might have a higher contribution to Lpr of the whole root system than the other component roots.

DOI： 10.1080/1343943X.2020.1730701

Plasticity in root system architecture of rice genotypes exhibited under different soil water distributions in soil profile

Kano-Nakata, M; Nakamura, T; Mitsuya, S; Yamauchi, A

PLANT PRODUCTION SCIENCE 22 巻 ( 4 ) 頁： 501 - 509 2019年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plant Production Science

The root system architecture (RSA) has been reported to be determined by several root traits such as branching, elongation, and growth angle. This study aimed to evaluate the genotypic variation of plasticity in RSA in response to different soil water distributions in a soil profile. IR64 (shallow root system), YTH183 (adapted to rainfed lowland conditions due to high plasticity in root elongation), and Kinandang Patong (KP–deep root system) were grown in PVC root boxes for 34 days under continuously waterlogged conditions and with soil moisture fluctuations (SMF). For SMF, watering was done from the top of the root box (TI-SMF) or from the bottom of the root box (BI-SMF). A water gradient was observed more clearly in BI-SMF than in TI-SMF, while mean soil moisture content in the root box was kept at around 23% (v/v) after first irrigation in both SMF treatments. RSA changed drastically with SMF in all cultivars, all of which tended to shift root distribution to deeper soil layers in response to SMF. Such changes in RSA resulted from different degrees of plasticity exhibited mainly in nodal root and L-type lateral root development. YTH183 showed a greater ability to change its root growth angle and thus its root distribution in the deeper soil layer compared to IR64 and KP under SMF, indicating that YTH183 could help to improve RSA in cultivars adapted to SMF.

DOI： 10.1080/1343943X.2019.1608836

Evaluation of rice grain yield and yield components of Nona Bokra chromosome segment substitution lines with the genetic background of Koshihikari, in a saline paddy field 国際誌

Mitsuya, S; Murakami, N; Sato, T; Kazama, T; Toriyama, K; Skoulding, NS; Kano-Nakata, M; Yamauchi, A

AOB PLANTS 11 巻 ( 5 ) 頁： plz040 2019年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AoB PLANTS

The ability to tolerate salt differs with the growth stages of rice and thus the yield components that are determined during various growth stages, are differentially affected by salt stress. In this study, we utilized chromosome segment substitution lines (CSSLs) from Nona Bokra, a salt-tolerant indica landrace, with the genetic background of Koshihikari, a salt-susceptible japonica variety. These were screened to find superior CSSLs under long-term saline conditions that showed higher grain yield and yield components in comparison to Koshihikari. One-month-old seedlings were transplanted into a paddy field without salinity. These were allowed to establish for 1 month further, then the field was flooded, with saline water maintained at 7.41 dS m-1 salinity until harvest. The experiments were performed twice, once in 2015 and a targeted study in 2016. Salt tolerance of growth and reproductive stage parameters was evaluated as the Salt Effect Index (SEI) which was computed as the difference in each parameter within each line between control and saline conditions. All CSSLs and Koshihikari showed a decrease in grain yield and yield components except panicle number under salinity. SL538 showed a higher SEI for grain yield compared with Koshihikari under salinity throughout the two experiments. This was attributed to the retained grain filling and harvest index, yet the mechanism was not due to maintaining Na+, Cl- and K+ homeostasis. Few other CSSLs showed greater SEI for grain weight under salinity compared with Koshihikari, which might be related to low concentration of Na+ in leaves and panicles. These data indicate that substitution of different Nona Bokra chromosome segments independently contributed to the maintenance of grain filling and grain weight of Koshihikari under saline conditions.

DOI： 10.1093/aobpla/plz040

'Kasalath' Allele in Nipponbare Background is Responsible for the Plasticity in Lateral Root Development of Rice under Soil Moisture Fluctuation Stress

Niones, JM; Suralta, RR; Inukai, Y; Kano-Nakata, M; Yamauchi, A

PHILIPPINE AGRICULTURAL SCIENTIST 102 巻 ( 3 ) 頁： 188 - 198 2019年9月

Soil Compaction Enhanced the Expression of Root Plasticity, Water and Nitrogen Uptake of Rice under Mild Drought with High N Fertilization

Tran, TT; Suralta, RR; Takeda, M; Mitsuya, S; Kano-Nakata, M; Yamauchi, A

PHILIPPINE AGRICULTURAL SCIENTIST 102 巻 ( 3 ) 頁： 199 - 210 2019年9月

Effect of nitrogen application on the expression of drought-induced root plasticity of upland NERICA rice 査読有り国際共著

Menge, D.M., Onyango, J.C., Yamauchi, A., Kano-Nakata, M., Asanuma, S., Thi, T.T., Inukai, Y., Kikuta, M., Makihara, D.

PLANT PRODUCTION SCIENCE 22 巻 ( 2 ) 頁： 180 - 191 2019年1月

Fundamental parenchyma cells are involved in Na+ and Cl- removal ability in rice leaf sheath

Neang, S; de Ocampo, M; Egdane, JA; Platten, JD; Ismail, AM; Skoulding, NS; Kano-Nakata, M; Yamauchi, A; Mitsuya, S

FUNCTIONAL PLANT BIOLOGY 46 巻 ( 8 ) 頁： 743 - 755 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Functional Plant Biology

Salt sensitivity in rice plants is associated with the accumulated amount of Na+ and Cl- in shoots and, more significantly, in photosynthetic tissues. Therefore, salt removal ability at the leaf sheath level is an important mechanism of salt tolerance. In the present study we attempted to determine whether rice leaf sheaths excluded Cl- as well as Na+, and to identify the tissues that were involved in the removal ability of both ions. In two rice genotypes, salt-tolerant FL478 and -sensitive IR29, leaf sheaths excluded Na+ and Cl- under NaCl treatment as estimated using their sheath: blade ratios. The sheath: blade ratio of Na+ but not of Cl-, was increased by NaCl treatment. Under NaCl treatment, Na+ concentration was higher in the basal leaf sheath, whereas Cl- concentration was higher in the middle and tip parts. At the tissue level, fundamental parenchyma cells of leaf sheaths retained the highest amounts of Na and Cl when treated with high amount of NaCl. These results imply that the leaf sheath potentially functions to remove excess Na+ and Cl- from xylem vessels in different locations along the axis, with the fundamental parenchyma cells of leaf sheaths being involved in over-accumulation of both Na+ and Cl-.

DOI： 10.1071/FP18318

Root plasticity for maintenance of productivity under abiotic stressed soil environments in rice: Progress and prospects

Suralta, RR; Kano-Nakata, M; Niones, JM; Inukai, Y; Kameoka, E; Tran, TT; Menge, D; Mitsuya, S; Yamauchi, A

FIELD CROPS RESEARCH 220 巻頁： 57 - 66 2018年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Field Crops Research

Roots play a number of important roles in crop adaptation to various abiotic stresses such as water stress. However, traits responsible for such adaptation may differ with environments. This paper reviews recent progress in our research on the functional roles of important root traits. We have been paying special attention to drought as well as to soil moisture fluctuations as prevailing water stresses, and the ability of the plant to change its development as environmental conditions change, which is known as phenotypic plasticity. We have been using various rice accessions/mapping populations such as the OryzaSNP panel, chromosome segment substitution lines (CSSL) derived from a Nipponbare and Kasalath cross, and IR64 introgression lines. The results consistently showed that, in addition to deep roots, the plasticity of root system development is a key trait for plant adaptation to water stress. We found that plasticity in the development of the entire root system as a function of the plasticity in lateral root development is important under progressive drought, while plasticity in lateral root development that is associated with aerenchyma formation is important under transient drought-to-waterlogged conditions. We quantitatively showed the contributions of root plasticity to dry matter production and yield through enhanced water uptake under such water stress. We also identified quantitative trait loci (QTLs) that are responsible for root plasticity. The importance of explicitly characterizing the nature of the stresses in the target areas is discussed in relation with designing an ideal root system, which is a primary requirement to define an actual breeding target for improving productivity in abiotic stress-prone soil environments.

DOI： 10.1016/j.fcr.2016.06.023

Plasticity in nodal root elongation through the hardpan triggered by rewatering during soil moisture fluctuation stress in rice

Suralta, RR; Niones, JM; Kano-Nakata, M; Tran, TT; Mitsuya, S; Yamauchi, A

SCIENTIFIC REPORTS 8 巻 ( 1 ) 頁： 4341 2018年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Scientific Reports

Rainfed lowland (RFL) rice fields have hardpans and experience soil moisture fluctuations (SMF) stress, which influence root system development. Here, we clarify the expression and timing of the plasticity in nodal root elongation through the hardpan under SMF and its contribution to shoot growth using a shallow-rooting IR64 and its deep-rooting introgression line, YTH304. Under SMF, soil moisture content had negative relationship with soil penetration resistance, regardless of hardpan bulk densities. YTH304 had greater root system below the hardpan than IR64 in hardpan with 1.50 but not in 1.70 g cm-3 bulk density (BD). YTH304 had greater plasticity in nodal root elongation through the hardpan than IR64 under SMF, which was clearly expressed during rewatering. YTH304 also had greater soil water uptake below the hardpan during drought and greater shoot growth than IR64. The results imply that deep root system development during SMF was due to the plasticity in nodal root elongation through the hardpan expressed during rewatering rather than during drought periods. This is against the long standing belief that active root elongation through the hardpan happens during drought. This also implies a need to revisit current root screening methods to identify rice lines with good hardpan penetration ability.

DOI： 10.1038/s41598-018-22809-5

Functional roles of root plasticity and its contribution to water uptake and dry matter production of CSSLs with the genetic background of KDML105 under soil moisture fluctuation

Owusu-Nketia, S; Siangliw, JL; Siangliw, M; Toojinda, T; Vanavichit, A; Ratsameejanphen, N; Ruangsiri, M; Sriwiset, S; Suralta, RR; Inukai, Y; Mitsuya, S; Kano-Nakata, M; Nguyen, DTN; Takuya, K; Yamauchi, A

PLANT PRODUCTION SCIENCE 21 巻 ( 3 ) 頁： 266 - 277 2018年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plant Production Science

Soil moisture fluctuation (SMF) stress due to erratic rainfall in rainfed lowland (RFL) rice ecosystems negatively affect production. Under such condition, root plasticity is one of the key traits that play important roles for plant adaptation. This study aimed to evaluate root plasticity expression and its functional roles in water uptake, dry matter production and yield under SMF using three chromosome segment substitution lines (CSSLs) with major genetic background of KDML105 and a common substituted segment in chromosome 8. The CSSLs showed greater shoot dry matter production than KDML105 under SMF, which was attributed to the maintenance of stomatal conductance resulting in higher grain yield. The root system development based on total root length of the CSSLs were significantly higher than that of KDML105 due to the promoted production of nodal and lateral roots. These results implied that the common substituted segments in chromosome 8 of the 3 CSSLs may be responsible for the expression of their root plasticity under SMF and contributed to the increase in water uptake and consequently dry matter production and yield. These CSSLs could be used as a good source of genetic material for drought resistance breeding programs targeting rainfed lowland condition with fluctuating soil moisture environments and for further genetic studies to elucidate mechanisms underlying root plasticity.

DOI： 10.1080/1343943X.2018.1477509

Genotypic variations in the plasticity of nodal root penetration through the hardpan during soil moisture fluctuations among four rice varieties

Nguyen, DTN; Suralta, RR; Kano-Nakata, M; Mitsuya, S; Owusu-Nketia, S; Yamauchi, A

PLANT PRODUCTION SCIENCE 21 巻 ( 2 ) 頁： 93 - 105 2018年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plant Production Science

Rainfed lowland rice fields are characterized by soil moisture fluctuations (SMF) and the presence of hardpan that impedes deep rooting and thus limits water extraction from deep soil layer during the periods of drought. In this study, we used rootboxes with three layers; shallow layer, artificial hardpan, and deep and wet layer below the hardpan, to evaluate differences in the plasticity of nodal roots elongation through the hardpan and promote root branching below the hardpan in response to SMF among four rice varieties; Sasanishiki, Habataki, Nipponbare, and Kasalath. Experiments were conducted during the summer and autumn seasons. Plasticity was computed as the difference in root traits within each variety between the SMF and continuously well-watered treatments. In both experiments, Habataki consistently tended to exhibit higher root plasticity than the other three varieties by increasing number of nodal roots that penetrated the hardpan during rewatering period in SMF, when the soil moisture increased and penetration resistance decreased. This root plasticity then contributed to greater water use at the deeper soil during the subsequent drought period and overall shoot dry matter production. Habataki had significantly higher δ13C value in roots at deep layer than roots at the shallow and hardpan layers under SMF, which may indicate that these were relatively newly grown roots as a consequence of root plasticity. This study also indicates that CSSLs derived from Sasanishiki and Habataki varieties may be suitable for the analysis of QTLs associated with root plasticity expression in rainfed lowland with hardpan and experiencing SMF.

DOI： 10.1080/1343943X.2018.1439757

Root plasticity under fluctuating soil moisture stress exhibited by backcross inbred line of a rice variety, Nipponbare carrying introgressed segments from KDML105 and detection of the associated QTLs

Owusu-Nketia, S; Inukai, Y; Ohashi, S; Suralta, RR; Doi, K; Mitsuya, S; Kano-Nakata, M; Niones, JM; Nguyen, DTN; Takuya, K; Makihara, D; Yamauchi, A

PLANT PRODUCTION SCIENCE 21 巻 ( 2 ) 頁： 106 - 122 2018年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plant Production Science

In rainfed lowland rice ecosystem, rice plants are often exposed to alternating recurrences of waterlogging and drought due to erratic rainfall. Such soil moisture fluctuation (SMF) which is completely different from simple or progressive drought could be stressful for plant growth, thereby causing reduction in yield. Root plasticity is one of the key traits that play important roles for plant adaptation under such conditions. This study aimed to evaluate root plasticity expression and its functional roles in dry matter production and yield under SMF using Nipponbare, KDML 105 and three backcross inbred lines (BILs) and to identify QTL(s) associated with root traits in response to SMF at two growth stages using Nipponbare/KDML105 F2 plants. A BIL, G3-3 showed higher shoot dry matter production and yield than Nipponbare due to its greater ability to maintain stomatal conductance concomitant with greater root system development caused by promoted production of nodal and lateral roots under SMF. QTLs were identified for total nodal root length, total lateral root length, total root length, number of nodal roots, and branching index under SMF at vegetative and reproductive stages. The QTLs detected at vegetative and reproductive stages were different. We discuss here that relationship between root system of G3-3 and the detected QTLs. Therefore, G3-3 and the identified QTLs could be useful genetic materials in breeding program for improving the adaptation of rice plants in target rainfed lowland areas.

DOI： 10.1080/1343943X.2018.1446759

Quantitative evaluation of plastic root responses to contiguous water gradient in rice 査読有り

Kano-Nakata M., Inukai Y., Siopongco J.D.L.C., Mitsuya S., Yamauchi A.

Plant Root 11 巻 ( 0 ) 頁： 70 - 78 2017年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：根研究学会

Root plasticity is the key trait for plant adaptation to environmental stresses. To quantify phenotypic plasticity to its full extent in potential, it needs to be evaluated under contiguous environmental changes. For that purpose, we used the combination of chromosome segment substitution lines (Nipponbare/Kasalath CSSLs) and line source sprinkler (LSS) system of irrigation. For analysis, we first attempted to apply the coefficient of variation (CV) and norm of reaction that have been used as the conventional approaches, and then propose a new approach for quantification of root plasticity. Results revealed that CV was not linked to root plasticity under contiguous water gradient in this study. In contrast, norm of reaction was linked to root plasticity and better explained with curve than linear, especially for CSSL50 (the most plastic genotypes) under such gradient. Based on the norm of reaction with curve, root plasticity was calculated using the difference in total root length between CSSLs and the recurrent parent, Nipponbare. Further analysis of root plasticity in relation to dry matter production was also done. By applying the new approach, we confirmed that root plasticity expression was affected by the intensities of drought stress and genotypes, indicating that such root plasticity is genetically controlled. In addition, root plasticity effectively contributed to the dry matter production under the drought conditions and maximized at around 20% of soil moisture content (–0.04 MPa). By using CSSLs and LSS system, we successfully evaluated root plasticity under contiguous water gradient.

DOI： 10.3117/plantroot.11.70