Phytochrome A requires jasmonate for photodestruction.
The plant photoreceptor phytochrome is organised in a small gene family with phytochrome A (phyA) being unique, because it is specifically degraded upon activation by light. This so called photodestruction is thought to be important for dynamic aspects of sensing such as measuring day length or shading by competitors. Signal-triggered proteolytic degradation has emerged as central element of signal crosstalk in plants during recent years, but many of the molecular players are still unknown. We therefore analyzed a jasmonate (JA)-deficient rice mutant, hebiba, that in several aspects resembles a mutant affected in photomorphogenesis. In this mutant, the photodestruction of phyA is delayed as shown by in vivo spectroscopy and Western blot analysis. Application of methyl-JA (MeJA) can rescue the delayed phyA photodestruction in the mutant in a time- and dose-dependent manner. Light regulation of phyA transcripts thought to be under control of stable phytochrome B (phyB) is still functional. The delayed photodestruction is accompanied by an elevated sensitivity of phytochrome-dependent growth responses to red and far-red light.
Riemann
Michael
M
Institute of Botany 1, Universität Karlsruhe, Kaiserstrasse 2, 76128 Karlsruhe, Germany. michael.riemann@bio.uka.de
Bouyer
Daniel
D
Hisada
Akiko
A
Müller
Axel
A
Yatou
Osamu
O
Weiler
Elmar W
EW
Takano
Makoto
M
Furuya
Masaki
M
Nick
Peter
P
D000085:Acetates / Q000494:pharmacology; D015153:Blotting, Western; D018548:Cotyledon / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D003517:Cyclopentanes / Q000378:metabolism* / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D007210:Indoleacetic Acids / Q000378:metabolism; D008027:Light; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D054883:Oxylipins / Q000378:metabolism* / Q000494:pharmacology; D051942:Phytochrome A / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000528:radiation effects*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D013997:Time Factors
D000085:Acetates; D003517:Cyclopentanes; D007210:Indoleacetic Acids; D054883:Oxylipins; D051942:Phytochrome A; D012333:RNA, Messenger; C011006:jasmonic acid; C072239:methyl jasmonate