Jasmonate and phytochrome A signaling in Arabidopsis wound and shade responses are integrated through JAZ1 stability.
Jasmonate (JA) activates plant defense, promotes pollen maturation, and suppresses plant growth. An emerging theme in JA biology is its involvement in light responses; here, we examine the interdependence of the JA- and light-signaling pathways in Arabidopsis thaliana. We demonstrate that mutants deficient in JA biosynthesis and signaling are deficient in a subset of high irradiance responses in far-red (FR) light. These mutants display exaggerated shade responses to low, but not high, R/FR ratio light, suggesting a role for JA in phytochrome A (phyA) signaling. Additionally, we demonstrate that the FR light-induced expression of transcription factor genes is dependent on CORONATINE INSENSITIVE1 (COI1), a central component of JA signaling, and is suppressed by JA. phyA mutants had reduced JA-regulated growth inhibition and VSP expression and increased content of cis-(+)-12-oxophytodienoic acid, an intermediate in JA biosynthesis. Significantly, COI1-mediated degradation of JASMONATE ZIM DOMAIN1-beta-glucuronidase (JAZ1-GUS) in response to mechanical wounding and JA treatment required phyA, and ectopic expression of JAZ1-GUS resulted in exaggerated shade responses. Together, these results indicate that JA and phyA signaling are integrated through degradation of the JAZ1 protein, and both are required for plant responses to light and stress.
Robson
Frances
F
School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom.
Okamoto
Haruko
H
Patrick
Elaine
E
Harris
Sue-Ré
SR
Wasternack
Claus
C
Brearley
Charles
C
Turner
John G
JG
D000872:Anthocyanins / Q000032:analysis; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002734:Chlorophyll / Q000032:analysis; D003517:Cyclopentanes / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated; D035264:Flowers / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D008027:Light; D009154:Mutation; D054883:Oxylipins / Q000378:metabolism*; D051942:Phytochrome A / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D015398:Signal Transduction
D000872:Anthocyanins; D029681:Arabidopsis Proteins; C112279:COI1 protein, Arabidopsis; D003517:Cyclopentanes; D005231:Fatty Acids, Unsaturated; D054883:Oxylipins; C497973:PHYA protein, Arabidopsis; D051942:Phytochrome A; D010937:Plant Growth Regulators; D018749:RNA, Plant; D002734:Chlorophyll; C025999:12-oxophytodienoic acid; C011006:jasmonic acid