Disruption of Arabidopsis CHY1 reveals an important role of metabolic status in plant cold stress signaling.
To study cold signaling, we screened for Arabidopsis mutants with altered cold-induced transcription of a firefly luciferase reporter gene driven by the CBF3 promoter (CBF3-LUC). One mutant, chy1-10, displayed reduced cold-induction of CBF3-LUC luminescence. RNA gel blot analysis revealed that expression of endogenous CBFs also was reduced in the chy1 mutant. chy1-10 mutant plants are more sensitive to freezing treatment than wild-type after cold acclimation. Both the wild-type and chy1 mutant plants are sensitive to darkness-induced starvation at warm temperatures, although chy1 plants are slightly more sensitive. This dark-sensitivity is suppressed by cold temperature in the wild-type but not in chy1. Constitutive CBF3 expression partially rescues the sensitivity of chy1-10 plants to dark treatment in the cold. The chy1 mutant accumulates higher levels of reactive oxygen species, and application of hydrogen peroxide can reduce cold-induction of CBF3-LUC in wild-type. Map-based cloning of the gene defective in the mutant revealed a nonsense mutation in CHY1, which encodes a peroxisomal beta-hydroxyisobutyryl (HIBYL)-CoA hydrolase needed for valine catabolism and fatty acid beta-oxidation. Our results suggest a role for peroxisomal metabolism in cold stress signaling, and plant tolerance to cold stress and darkness-induced starvation.
Dong
Chun-Hai
CH
Department of Botany and Plant Science, 2150 Batchelor Hall, University of California at Riverside, Riverside, CA 92521, USA.
Zolman
Bethany K
BK
Bartel
Bonnie
B
Lee
Byeong-ha
BH
Stevenson
Becky
B
Agarwal
Manu
M
Zhu
Jian-Kang
JK
D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D003080:Cold Temperature; D011401:Promoter Regions, Genetic; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction
D029681:Arabidopsis Proteins; D017382:Reactive Oxygen Species