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García-Gómez ML, Reyes-Hernández BJ, Sahoo DP, Napsucialy-Mendivil S, Quintana-Armas AX, Pedroza-García JA, Shishkova S, Torres-Martínez HH, Pacheco-Escobedo MA, Dubrovsky JG. A mutation in THREONINE SYNTHASE 1 uncouples proliferation and transition domains of the root apical meristem: experimental evidence and in silico proposed mechanism. Development 2022; 149:278438. [PMID: 36278862 PMCID: PMC9796171 DOI: 10.1242/dev.200899] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 10/10/2022] [Indexed: 11/11/2022]
Abstract
A continuum from stem to transit-amplifying to a differentiated cell state is a common theme in multicellular organisms. In the plant root apical meristem (RAM), transit-amplifying cells are organized into two domains: cells from the proliferation domain (PD) are displaced to the transition domain (TD), suggesting that both domains are necessarily coupled. Here, we show that in the Arabidopsis thaliana mto2-2 mutant, in which threonine (Thr) synthesis is affected, the RAM lacks the PD. Through a combination of cell length profile analysis, mathematical modeling and molecular markers, we establish that the PD and TD can be uncoupled. Remarkably, although the RAM of mto2-2 is represented solely by the TD, the known factors of RAM maintenance and auxin signaling are expressed in the mutant. Mathematical modeling predicts that the stem cell niche depends on Thr metabolism and that, when disturbed, the normal continuum of cell states becomes aborted.
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Affiliation(s)
- Monica L. García-Gómez
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad, 2001, Cuernavaca 62250, Mexico
| | - Blanca J. Reyes-Hernández
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad, 2001, Cuernavaca 62250, Mexico
| | - Debee P. Sahoo
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad, 2001, Cuernavaca 62250, Mexico
| | - Selene Napsucialy-Mendivil
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad, 2001, Cuernavaca 62250, Mexico
| | - Aranza X. Quintana-Armas
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad, 2001, Cuernavaca 62250, Mexico
| | - José A. Pedroza-García
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad, 2001, Cuernavaca 62250, Mexico
| | - Svetlana Shishkova
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad, 2001, Cuernavaca 62250, Mexico
| | - Héctor H. Torres-Martínez
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad, 2001, Cuernavaca 62250, Mexico
| | - Mario A. Pacheco-Escobedo
- Facultad de Ciencias de la Salud, Universidad Tecnológica de México – UNITEC MÉXICO – Campus Atizapán, Av. Calacoaya 7, Atizapán de Zaragoza, Estado de México, 52970, Mexico
| | - Joseph G. Dubrovsky
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Av. Universidad, 2001, Cuernavaca 62250, Mexico,Author for correspondence ()
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Reyes-Hernández BJ, Shishkova S, Amir R, Quintana-Armas AX, Napsucialy-Mendivil S, Cervantes-Gamez RG, Torres-Martínez HH, Montiel J, Wood CD, Dubrovsky JG. Root stem cell niche maintenance and apical meristem activity critically depend on THREONINE SYNTHASE1. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3835-3849. [PMID: 30972413 DOI: 10.1093/jxb/erz165] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 03/22/2019] [Indexed: 05/23/2023]
Abstract
Indeterminate root growth depends on the stem cell niche (SCN) and root apical meristem (RAM) maintenance whose regulation permits plasticity in root system formation. Using a forward genetics approach, we isolated the moots koom1 ('short root' in Mayan) mutant that shows complete primary RAM exhaustion and abolished SCN activity. We identified that this phenotype is caused by a point mutation in the METHIONINE OVERACCUMULATOR2 (MTO2) gene that encodes THREONINE SYNTHASE1 and renamed the mutant as mto2-2. The amino acid profile showed drastic changes, most notorious of which was accumulation of methionine. In non-allelic mto1-1 (Arabidopsis thaliana cystathionine gamma-synthetase1) and mto3-1 (S-adenosylmethionine synthetase) mutants, both with an increased methionine level, the RAM size was similar to that of the wild type, suggesting that methionine overaccumulation itself did not cause RAM exhaustion in mto2 mutants. When mto2-2 RAM is not yet completely exhausted, exogenous threonine induced de novo SCN establishment and root growth recovery. The threonine-dependent RAM re-establishment in mto2-2 suggests that threonine is a limiting factor for RAM maintenance. In the root, MTO2 was predominantly expressed in the RAM. The essential role of threonine in mouse embryonic stem cells and in RAM maintenance suggests that common regulatory mechanisms may operate in plant and animal SCN maintenance.
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Affiliation(s)
- Blanca Jazmín Reyes-Hernández
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Svetlana Shishkova
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Rachel Amir
- Laboratory of Plant Science, MIGAL-Galilee Research Institute, Kiryat Shmona, Israel
- Tel-Hai College, Upper Galilee, Israel
| | - Aranza Xhaly Quintana-Armas
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Selene Napsucialy-Mendivil
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Rocio Guadalupe Cervantes-Gamez
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Héctor Hugo Torres-Martínez
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Jesús Montiel
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Christopher D Wood
- Laboratorio Nacional de Microscopía Avanzada, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Joseph G Dubrovsky
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
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