GH3-mediated auxin homeostasis links growth regulation with stress adaptation response in Arabidopsis.
Plants constantly monitor environmental fluctuations to optimize their growth and metabolism. One example is adaptive growth occurring in response to biotic and abiotic stresses. Here, we demonstrate that GH3-mediated auxin homeostasis is an essential constituent of the complex network of auxin actions that regulates stress adaptation responses in Arabidopsis. Endogenous auxin pool is regulated, at least in part, through negative feedback by a group of auxin-inducible GH3 genes encoding auxin-conjugating enzymes. An Arabidopsis mutant, wes1-D, in which a GH3 gene WES1 is activated by nearby insertion of the (35)S enhancer, exhibited auxin-deficient traits, including reduced growth and altered leaf shape. Interestingly, WES1 is also induced by various stress conditions as well as by salicylic acid and abscisic acid. Accordingly, wes1-D was resistant to both biotic and abiotic stresses, and stress-responsive genes, such as pathogenesis-related genes and CBF genes, were upregulated in this mutant. In contrast, a T-DNA insertional mutant showed reduced stress resistance. We therefore propose that GH3-mediated growth suppression directs reallocation of metabolic resources to resistance establishment and represents the fitness costs of induced resistance.
Park
Jung-Eun
JE
Molecular Signaling Laboratory, Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
Park
Ju-Young
JY
School of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-742, Korea.
Kim
Youn-Sung
YS
Molecular Signaling Laboratory, Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
Staswick
Paul E
PE
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583.
Jeon
Jin
J
Department of Plant Biotechnology, Agricultural Plant Stress Research Center and Biotechnology Research Institute, Chonnam National University, Gwangju 500-757, Korea.
Yun
Ju
J
Molecular Signaling Laboratory, Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
Kim
Sun-Young
SY
Molecular Signaling Laboratory, Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
Kim
Jungmook
J
Department of Plant Biotechnology, Agricultural Plant Stress Research Center and Biotechnology Research Institute, Chonnam National University, Gwangju 500-757, Korea.
Lee
Yong-Hwan
YH
School of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-742, Korea.
Park
Chung-Mo
CM
Molecular Signaling Laboratory, Department of Chemistry, Seoul National University, Seoul 151-742, Korea. Electronic address: cmpark@snu.ac.kr.
D000222:Adaptation, Physiological / Q000502:physiology*; D017360:Arabidopsis / Q000201:enzymology / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000502:physiology*; D005966:Glucuronidase / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D007210:Indoleacetic Acids / Q000378:metabolism*; D009687:Nuclear Proteins / Q000502:physiology*; D018384:Oxidative Stress / Q000502:physiology*
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C109765:ETT protein, Arabidopsis; C491592:IAA1 protein, Arabidopsis; D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D005966:Glucuronidase