Auxin increases the hydrogen peroxide (H2O2) concentration in tomato (Solanum lycopersicum) root tips while inhibiting root growth
Por:
Ivanchenko M.G., Den Os D., Monshausen G.B., Dubrovsky J.G., Bednarova, A, Krishnan N.
Publicada:
1 oct 2013
Categoría:
Plant Science
Resumen:
Background and AimsThe hormone auxin and reactive oxygen species (ROS) regulate root elongation, but the interactions between the two pathways are not well understood. The aim of this study was to investigate how auxin interacts with ROS in regulating root elongation in tomato, Solanum lycopersicum. MethodsWild-type and auxin-resistant mutant, diageotropica (dgt), of tomato (S. lycopersicum 'Ailsa Craig') were characterized in terms of root apical meristem and elongation zone histology, expression of the cell-cycle marker gene Sl-CycB1;1, accumulation of ROS, response to auxin and hydrogen peroxide (H 2O2), and expression of ROS-related mRNAs.Key ResultsThe dgt mutant exhibited histological defects in the root apical meristem and elongation zone and displayed a constitutively increased level of hydrogen peroxide (H2O2) in the root tip, part of which was detected in the apoplast. Treatments of wild-type with auxin increased the H2O2 concentration in the root tip in a dose-dependent manner. Auxin and H2O2 elicited similar inhibition of cell elongation while bringing forth differential responses in terms of meristem length and number of cells in the elongation zone. Auxin treatments affected the expression of mRNAs of ROS-scavenging enzymes and less significantly mRNAs related to antioxidant level. The dgt mutation resulted in resistance to both auxin and H2O2 and affected profoundly the expression of mRNAs related to antioxidant level. Conclusions The results indicate that auxin regulates the level of H2O2 in the root tip, so increasing the auxin level triggers accumulation of H2O2 leading to inhibition of root cell elongation and root growth. The dgt mutation affects this pathway by reducing the auxin responsiveness of tissues and by disrupting the H2O2 homeostasis in the root tip. © 2013 The Author. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.
Filiaciones:
Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Biol Mol Plantas, Cuernavaca 62250, Morelos, Mexico
Department of Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, OR 97331, United States
Biology Department, Penn State University, 208 Mueller Lab, University Park, PA 16802, United States
University of Groningen, Ecophysiology of Plants, Centre for Ecological and Evolutionary Studies, 9700 CC Groningen, Netherlands
Departamento de Biologia Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, A. P. 510-3, 62250 Cuernavaca, Morelos, Mexico
Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, United States
Institute of Entomology, Biology Centre, South Bohemian University, Branišovská 31, Ceské Budejovice, 370 05-CZ, Czech Republic
All Open Access, Bronze
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