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Lucob-Agustin N, Kawai T, Takahashi-Nosaka M, Kano-Nakata M, Wainaina CM, Hasegawa T, Inari-Ikeda M, Sato M, Tsuji H, Yamauchi A, Inukai Y. WEG1, which encodes a cell wall hydroxyproline-rich glycoprotein, is essential for parental root elongation controlling lateral root formation in rice. PHYSIOLOGIA PLANTARUM 2020; 169:214-227. [PMID: 31925781 DOI: 10.1111/ppl.13063] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 12/18/2019] [Accepted: 12/19/2019] [Indexed: 05/25/2023]
Abstract
Lateral roots (LRs) determine the overall root system architecture, thus enabling plants to efficiently explore their underground environment for water and nutrients. However, the mechanisms regulating LR development are poorly understood in monocotyledonous plants. We characterized a rice mutant, wavy root elongation growth 1 (weg1), that produced higher number of long and thick LRs (L-type LRs) formed from the curvatures of its wavy parental roots caused by asymmetric cell growth in the elongation zone. Consistent with this phenotype, was the expression of the WEG1 gene, which encodes a putative member of the hydroxyproline-rich glycoprotein family that regulates cell wall extensibility, in the root elongation zone. The asymmetric elongation growth in roots is well known to be regulated by auxin, but we found that the distribution of auxin at the apical region of the mutant and the wild-type roots was symmetric suggesting that the wavy root phenotype in rice is independent of auxin. However, the accumulation of auxin at the convex side of the curvatures, the site of L-type LR formation, suggested that auxin likely induced the formation of L-type LRs. This was supported by the need of a high amount of exogenous auxin to induce the formation of L-type LRs. These results suggest that the MNU-induced weg1 mutated gene regulates the auxin-independent parental root elongation that controls the number of likely auxin-induced L-type LRs, thus reflecting its importance in improving rice root architecture.
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Affiliation(s)
- Nonawin Lucob-Agustin
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Tsubasa Kawai
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Misuzu Takahashi-Nosaka
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Mana Kano-Nakata
- International Center for Research and Education in Agriculture, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Cornelius M Wainaina
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Tomomi Hasegawa
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Mayuko Inari-Ikeda
- International Center for Research and Education in Agriculture, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Moeko Sato
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, 244-0813, Japan
| | - Hiroyuki Tsuji
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, 244-0813, Japan
| | - Akira Yamauchi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Yoshiaki Inukai
- International Center for Research and Education in Agriculture, Nagoya University, Nagoya, Aichi, 464-8601, Japan
- PREST, JST, Kawaguchi, Saitama, 332-0012, Japan
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Le Deunff E, Lecourt J, Malagoli P. Fine-tuning of root elongation by ethylene: a tool to study dynamic structure-function relationships between root architecture and nitrate absorption. ANNALS OF BOTANY 2016; 118:607-620. [PMID: 27411681 PMCID: PMC5055632 DOI: 10.1093/aob/mcw123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/26/2016] [Accepted: 05/12/2016] [Indexed: 05/08/2023]
Abstract
Background Recently developed genetic and pharmacological approaches have been used to explore NO3-/ethylene signalling interactions and how the modifications in root architecture by pharmacological modulation of ethylene biosynthesis affect nitrate uptake. Key Results Structure-function studies combined with recent approaches to chemical genomics highlight the non-specificity of commonly used inhibitors of ethylene biosynthesis such as AVG (l-aminoethoxyvinylglycine). Indeed, AVG inhibits aminotransferases such as ACC synthase (ACS) and tryptophan aminotransferase (TAA) involved in ethylene and auxin biosynthesis but also some aminotransferases implied in nitrogen (N) metabolism. In this framework, it can be assumed that the products of nitrate assimilation and hormones may interact through a hub in carbon (C) and N metabolism to drive the root morphogenetic programme (RMP). Although ethylene/auxin interactions play a major role in cell division and elongation in root meristems, shaping of the root system depends also on energetic considerations. Based on this finding, the analysis is extended to nutrient ion-hormone interactions assuming a fractal or constructal model for root development. Conclusion Therefore, the tight control of root structure-function in the RMP may explain why over-expressing nitrate transporter genes to decouple structure-function relationships and improve nitrogen use efficiency (NUE) has been unsuccessful.
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Affiliation(s)
- Erwan Le Deunff
- Université de Caen Basse-Normandie, UMR Écophysiologie Végétale & Agronomie, Nutritions NCS, F-14032 Caen, France
- INRA, UMR 950, Écophysiologie Végétale & Agronomie, Nutritions NCS, F-14032 Caen, France
| | - Julien Lecourt
- East Malling Research, New Road, East Malling ME19 6BJ, Kent, UK
| | - Philippe Malagoli
- Université Blaise Pascal-INRA, 24, avenue des Landais, BP 80 006, F-63177 Aubière, France
- INRA, UMR 547 PIAF, Bâtiment Biologie Végétale Recherche, BP 80 006, F-63177 Aubière, France
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Richterová-Kučerová D, Kollárová K, Zelko I, Vatehová Z, Lišková D. How do galactoglucomannan oligosaccharides regulate cell growth in epidermal and cortical tissues of mung bean seedlings? PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 57:154-8. [PMID: 22705590 DOI: 10.1016/j.plaphy.2012.05.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 05/15/2012] [Indexed: 05/26/2023]
Abstract
Biologically active galactoglucomannan oligosaccharides (GGMOs) alone or in combination with IBA stimulate primary root elongation and inhibit hypocotyl elongation in mung bean (Vigna radiata (L.) Wilczek) seedlings. For a more detailed view of GGMOs effect in these processes, the present work is focused on cell growth in selected tissues (epidermis and primary cortex) and on xylem formation. The GGMOs effect on tissue level has not been studied so far. The results show that GGMOs-induced stimulation of primary root growth is mainly caused by enhancing cell elongation (and in less extent by cell production rate) in all tissues observed. Xylem elements were formed at longer distance from the root tip than in the control. In hypocotyl GGMOs reduced cell elongation. IBA in roots caused decrease of cell elongation and cell production rate and acceleration of xylem maturation; in hypocotyls IBA strongly stimulated cell elongation. Application of GGMOs with IBA resulted in increase of cell elongation, cell production rate and delay of xylem maturation in roots. In GGMOs + IBA treated hypocotyls, cell length was decreased to 50% compared to IBA. Based on our results it can be concluded that GGMOs induced elongation growth in mung bean seedlings was caused by increased cell production rate and cell elongation and was accompanied with delay of xylem maturation.
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