The Arabidopsis ATR1 Myb transcription factor controls indolic glucosinolate homeostasis.
Plants derive a number of important secondary metabolites from the amino acid tryptophan (Trp), including the growth regulator indole-3-acetic acid (IAA) and defense compounds against pathogens and herbivores. In previous work, we found that a dominant overexpression allele of the Arabidopsis (Arabidopsis thaliana) Myb transcription factor ATR1, atr1D, activates expression of a Trp synthesis gene as well as the Trp-metabolizing genes CYP79B2, CYP79B3, and CYP83B1, which encode enzymes implicated in production of IAA and indolic glucosinolate (IG) antiherbivore compounds. Here, we show that ATR1 overexpression confers elevated levels of IAA and IGs. In addition, we show that an atr1 loss-of-function mutation impairs expression of IG synthesis genes and confers reduced IG levels. Furthermore, the atr1-defective mutation suppresses Trp gene dysregulation in a cyp83B1 mutant background. Together, this work implicates ATR1 as a key homeostatic regulator of Trp metabolism and suggests that ATR1 can be manipulated to coordinately control the suite of enzymes that synthesize IGs.
Celenza
John L
JL
Department of Biology, Boston University, Boston, Massachusetts 02215, USA.
Quiel
Juan A
JA
Smolen
Gromoslaw A
GA
Merrikh
Houra
H
Silvestro
Angela R
AR
Normanly
Jennifer
J
Bender
Judith
J
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D005961:Glucosinolates / Q000378:metabolism*; D006706:Homeostasis; D007210:Indoleacetic Acids / Q000378:metabolism; D015394:Molecular Structure; D009154:Mutation; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D020598:Proto-Oncogene Proteins c-myb / Q000235:genetics / Q000502:physiology*; D014364:Tryptophan / Q000096:biosynthesis / Q000737:chemistry; D015854:Up-Regulation
C511988:ATR1 protein, Arabidopsis; D029681:Arabidopsis Proteins; C511989:CPC protein, Arabidopsis; D005961:Glucosinolates; D007210:Indoleacetic Acids; D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb; C030737:indoleacetic acid; D014364:Tryptophan