Dynamic regulation of auxin oxidase and conjugating enzymes <i>AtDAO1</i> and <i>GH3</i> modulates auxin homeostasis. Mellor, N., Band, L. R., Pěnčík, A., Novák, O., Rashed, A., Holman, T., Wilson, M. H., Voß, U., Bishopp, A., King, J. R., Ljung, K., Bennett, M. J., & Owen, M. R. Proceedings of the National Academy of Sciences, 113(39):11022–11027, September, 2016.
Dynamic regulation of auxin oxidase and conjugating enzymes <i>AtDAO1</i> and <i>GH3</i> modulates auxin homeostasis [link]Paper  doi  abstract   bibtex   
The hormone auxin is a key regulator of plant growth and development, and great progress has been made understanding auxin transport and signaling. Here, we show that auxin metabolism and homeostasis are also regulated in a complex manner. The principal auxin degradation pathways in Arabidopsis include oxidation by Arabidopsis thaliana gene DIOXYGENASE FOR AUXIN OXIDATION 1/2 (AtDAO1/2) and conjugation by Gretchen Hagen3s (GH3s). Metabolic profiling of dao1-1 root tissues revealed a 50% decrease in the oxidation product 2-oxoindole-3-acetic acid (oxIAA) and increases in the conjugated forms indole-3-acetic acid aspartic acid (IAA-Asp) and indole-3-acetic acid glutamic acid (IAA-Glu) of 438- and 240-fold, respectively, whereas auxin remains close to the WT. By fitting parameter values to a mathematical model of these metabolic pathways, we show that, in addition to reduced oxidation, both auxin biosynthesis and conjugation are increased in dao1-1 . Transcripts of AtDAO1 and GH3 genes increase in response to auxin over different timescales and concentration ranges. Including this regulation of AtDAO1 and GH3 in an extended model reveals that auxin oxidation is more important for auxin homoeostasis at lower hormone concentrations, whereas auxin conjugation is most significant at high auxin levels. Finally, embedding our homeostasis model in a multicellular simulation to assess the spatial effect of the dao1-1 mutant shows that auxin increases in outer root tissues in agreement with the dao1-1 mutant root hair phenotype. We conclude that auxin homeostasis is dependent on AtDAO1 , acting in concert with GH3 , to maintain auxin at optimal levels for plant growth and development.
@article{mellor_dynamic_2016,
	title = {Dynamic regulation of auxin oxidase and conjugating enzymes \textit{{AtDAO1}} and \textit{{GH3}} modulates auxin homeostasis},
	volume = {113},
	issn = {0027-8424, 1091-6490},
	url = {http://www.pnas.org/lookup/doi/10.1073/pnas.1604458113},
	doi = {10/f3t6ch},
	abstract = {The hormone auxin is a key regulator of plant growth and development, and great progress has been made understanding auxin transport and signaling. Here, we show that auxin metabolism and homeostasis are also regulated in a complex manner. The principal auxin degradation pathways in
              Arabidopsis
              include oxidation by
              Arabidopsis thaliana
              gene
              DIOXYGENASE FOR AUXIN OXIDATION 1/2
              (AtDAO1/2) and conjugation by Gretchen Hagen3s (GH3s). Metabolic profiling of
              dao1-1
              root tissues revealed a 50\% decrease in the oxidation product 2-oxoindole-3-acetic acid (oxIAA) and increases in the conjugated forms indole-3-acetic acid aspartic acid (IAA-Asp) and indole-3-acetic acid glutamic acid (IAA-Glu) of 438- and 240-fold, respectively, whereas auxin remains close to the WT. By fitting parameter values to a mathematical model of these metabolic pathways, we show that, in addition to reduced oxidation, both auxin biosynthesis and conjugation are increased in
              dao1-1
              . Transcripts of
              AtDAO1
              and
              GH3
              genes increase in response to auxin over different timescales and concentration ranges. Including this regulation of
              AtDAO1
              and
              GH3
              in an extended model reveals that auxin oxidation is more important for auxin homoeostasis at lower hormone concentrations, whereas auxin conjugation is most significant at high auxin levels. Finally, embedding our homeostasis model in a multicellular simulation to assess the spatial effect of the
              dao1-1
              mutant shows that auxin increases in outer root tissues in agreement with the
              dao1-1
              mutant root hair phenotype. We conclude that auxin homeostasis is dependent on
              AtDAO1
              , acting in concert with
              GH3
              , to maintain auxin at optimal levels for plant growth and development.},
	language = {en},
	number = {39},
	urldate = {2021-06-07},
	journal = {Proceedings of the National Academy of Sciences},
	author = {Mellor, Nathan and Band, Leah R. and Pěnčík, Aleš and Novák, Ondřej and Rashed, Afaf and Holman, Tara and Wilson, Michael H. and Voß, Ute and Bishopp, Anthony and King, John R. and Ljung, Karin and Bennett, Malcolm J. and Owen, Markus R.},
	month = sep,
	year = {2016},
	pages = {11022--11027},
}

Downloads: 0