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DAO1 catalyzes temporal and tissue-specific oxidative inactivation of auxin in Arabidopsis thaliana.
Proc Natl Acad Sci U S A. 2016 09 27; 113(39):11010-5.PN

Abstract

Tight homeostatic regulation of the phytohormone auxin [indole-3-acetic acid (IAA)] is essential to plant growth. Auxin biosynthetic pathways and the processes that inactivate auxin by conjugation to amino acids and sugars have been thoroughly characterized. However, the enzyme that catalyzes oxidation of IAA to its primary catabolite 2-oxindole-3-acetic acid (oxIAA) remains uncharacterized. Here, we show that DIOXYGENASE FOR AUXIN OXIDATION 1 (DAO1) catalyzes formation of oxIAA in vitro and in vivo and that this mechanism regulates auxin homeostasis and plant growth. Null dao1-1 mutants contain 95% less oxIAA compared with wild type, and complementation of dao1 restores wild-type oxIAA levels, indicating that DAO1 is the primary IAA oxidase in seedlings. Furthermore, dao1 loss of function plants have altered morphology, including larger cotyledons, increased lateral root density, delayed sepal opening, elongated pistils, and reduced fertility in the primary inflorescence stem. These phenotypes are tightly correlated with DAO1 spatiotemporal expression patterns as shown by DAO1pro:β-glucuronidase (GUS) activity and DAO1pro:YFP-DAO1 signals, and transformation with DAO1pro:YFP-DAO1 complemented the mutant phenotypes. The dominant dao1-2D mutant has increased oxIAA levels and decreased stature with shorter leaves and inflorescence stems, thus supporting DAO1 IAA oxidase function in vivo. A second isoform, DAO2, is very weakly expressed in seedling root apices. Together, these data confirm that IAA oxidation by DAO1 is the principal auxin catabolic process in Arabidopsis and that localized IAA oxidation plays a role in plant morphogenesis.

Authors+Show Affiliations

Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742;Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691; Ohio Agricultural Research and Development Center Metabolite Analysis Cluster, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691;Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742;Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742; Plant Protection and Animal Health, Forestry, Agronomy, Universidade Estadual de São Paulo, Sao Paulo, Brazil.Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742;Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691; Ohio Agricultural Research and Development Center Metabolite Analysis Cluster, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691;Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742; Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742; wapeer@umd.edu.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

27651492

Citation

Zhang, Jun, et al. "DAO1 Catalyzes Temporal and Tissue-specific Oxidative Inactivation of Auxin in Arabidopsis Thaliana." Proceedings of the National Academy of Sciences of the United States of America, vol. 113, no. 39, 2016, pp. 11010-5.
Zhang J, Lin JE, Harris C, et al. DAO1 catalyzes temporal and tissue-specific oxidative inactivation of auxin in Arabidopsis thaliana. Proc Natl Acad Sci U S A. 2016;113(39):11010-5.
Zhang, J., Lin, J. E., Harris, C., Campos Mastrotti Pereira, F., Wu, F., Blakeslee, J. J., & Peer, W. A. (2016). DAO1 catalyzes temporal and tissue-specific oxidative inactivation of auxin in Arabidopsis thaliana. Proceedings of the National Academy of Sciences of the United States of America, 113(39), 11010-5. https://doi.org/10.1073/pnas.1604769113
Zhang J, et al. DAO1 Catalyzes Temporal and Tissue-specific Oxidative Inactivation of Auxin in Arabidopsis Thaliana. Proc Natl Acad Sci U S A. 2016 09 27;113(39):11010-5. PubMed PMID: 27651492.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - DAO1 catalyzes temporal and tissue-specific oxidative inactivation of auxin in Arabidopsis thaliana. AU - Zhang,Jun, AU - Lin,Jinshan Ella, AU - Harris,Chinchu, AU - Campos Mastrotti Pereira,Fernanda, AU - Wu,Fan, AU - Blakeslee,Joshua J, AU - Peer,Wendy Ann, Y1 - 2016/09/20/ PY - 2016/9/22/entrez PY - 2016/9/22/pubmed PY - 2018/1/27/medline KW - auxin homeostasis KW - auxin oxidase KW - auxin oxidation KW - flowers KW - lateral roots SP - 11010 EP - 5 JF - Proceedings of the National Academy of Sciences of the United States of America JO - Proc Natl Acad Sci U S A VL - 113 IS - 39 N2 - Tight homeostatic regulation of the phytohormone auxin [indole-3-acetic acid (IAA)] is essential to plant growth. Auxin biosynthetic pathways and the processes that inactivate auxin by conjugation to amino acids and sugars have been thoroughly characterized. However, the enzyme that catalyzes oxidation of IAA to its primary catabolite 2-oxindole-3-acetic acid (oxIAA) remains uncharacterized. Here, we show that DIOXYGENASE FOR AUXIN OXIDATION 1 (DAO1) catalyzes formation of oxIAA in vitro and in vivo and that this mechanism regulates auxin homeostasis and plant growth. Null dao1-1 mutants contain 95% less oxIAA compared with wild type, and complementation of dao1 restores wild-type oxIAA levels, indicating that DAO1 is the primary IAA oxidase in seedlings. Furthermore, dao1 loss of function plants have altered morphology, including larger cotyledons, increased lateral root density, delayed sepal opening, elongated pistils, and reduced fertility in the primary inflorescence stem. These phenotypes are tightly correlated with DAO1 spatiotemporal expression patterns as shown by DAO1pro:β-glucuronidase (GUS) activity and DAO1pro:YFP-DAO1 signals, and transformation with DAO1pro:YFP-DAO1 complemented the mutant phenotypes. The dominant dao1-2D mutant has increased oxIAA levels and decreased stature with shorter leaves and inflorescence stems, thus supporting DAO1 IAA oxidase function in vivo. A second isoform, DAO2, is very weakly expressed in seedling root apices. Together, these data confirm that IAA oxidation by DAO1 is the principal auxin catabolic process in Arabidopsis and that localized IAA oxidation plays a role in plant morphogenesis. SN - 1091-6490 UR - https://www.unboundmedicine.com/medline/citation/27651492/DAO1_catalyzes_temporal_and_tissue_specific_oxidative_inactivation_of_auxin_in_Arabidopsis_thaliana_ L2 - http://www.pnas.org/cgi/pmidlookup?view=long&pmid=27651492 DB - PRIME DP - Unbound Medicine ER -