Root stem cell niche maintenance and apical meristem activity critically depend on THREONINE SYNTHASE1
Por:
Reyes-Hernández B.J., Shishkova, Svetlana, Amir, Rachel, Quintana-Armas A.X., Napsucialy-Mendivil, Selene, Cervantes-Gamez R.G., Torres-Martínez H.H., Montiel, Jesus, Wood, Christopher D., Dubrovsky, Joseph G.
Publicada:
1 ene 2019
Resumen:
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. © The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Filiaciones:
Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, México
Laboratory of Plant Science, MIGAL-Galilee Research Institute, Kiryat Shmona, Israel
Tel-Hai College, Upper Galilee, Israel
Laboratorio Nacional de Microscopía Avanzada, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
UNAM, Inst Biotecnol, Dept Biol Mol Plantas, Apartado Postal 510-3, Cuernavaca 62250, Morelos, Mexico
Heidelberg Univ, Ctr Organismal Studies, D-69120 Heidelberg, Germany
MIGAL Galilee Res Inst, Lab Plant Sci, IL-11016 Kiryat Shmona, Israel
Tel Hai Coll, IL-11016 Upper Galilee, Israel
Univ Guadalajara, Dept Estudios Desarrollo Sustentable Zonas Coster, Gomez Farias 82, Cihuatlan 48980, Jalisco, Mexico
Aarhus Univ, Ctr Carbohydrate Recognit & Signaling, Dept Mol Biol & Genet, DK-8000 Aarhus C, Denmark
UNAM, Inst Biotecnol, Lab Nacl Microscopia Avanzada, Apartado Postal 510-3, Cuernavaca 62250, Morelos, Mexico
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