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Sequential and coordinated action of phytochromes A and B during Arabidopsis stem growth revealed by kinetic analysisPhotoreceptor proteins of the phytochrome family mediate light-induced inhibition of stem (hypocotyl) elongation during the development of photoautotrophy in seedlings. Analyses of overt mutant phenotypes have established the importance of phytochromes A and B (phyA and phyB) in this developmental process, but kinetic information that would augment emerging molecular models of phytochrome signal transduction is absent. We have addressed this deficiency by genetically dissecting phytochrome-response kinetics, after having solved the technical issues that previously limited growth studies of small Arabidopsis seedlings. We show here, with resolution on the order of minutes, that phyA initiated hypocotyl growth inhibition upon the onset of continuous red light. This primary contribution of phyA began to decrease after 3 hr of irradiation, the same time at which immunochemically detectable phyA disappeared and an exclusively phyB-dependent phase of inhibition began. The sequential and coordinated actions of phyA and phyB in red light were not observed in far-red light, which inhibited growth persistently through an exclusively phyA-mediated pathway.
Document ID
20040141765
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Parks, B. M.
(University of Wisconsin 430 Lincoln Drive, Madison, Wisconsin 53706, United States)
Spalding, E. P.
Evans, M. L.
Date Acquired
August 22, 2013
Publication Date
November 23, 1999
Publication Information
Publication: Proceedings of the National Academy of Sciences of the United States of America
Volume: 96
Issue: 24
ISSN: 0027-8424
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Plant Biology
Non-NASA Center

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