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ARS Home » Pacific West Area » Albany, California » Plant Gene Expression Center » Research » Publications at this Location » Publication #169147
Title: EXPRESSION PROFILING OF PHYB MUTANT DEMONSTRATES SUBSTANTIAL CONTRIBUTION OF OTHER PHYTOCHROMES TO RED-LIGHT-REGULATED GENE EXPRESSION DURING SEEDLING DE-ETIOLATION.

Author
item TEPPERMAN, JAMES - ARS-UCB PLNT GENE EXP CTR
item HUDSON, MATTHEW - ARS-UCB PLNT GENE EXP CTR
item KHANNA, RAJINISH - ARS-UCB PLNT GENE EXP CTR
item ZHU, TONG - TMRI SAN DIEGO CA
item CHANG, SHERMAN - TMRI SAN DIEGO CA
item WANG, XUN - TMRI SAN DIEGO CA
item QUAIL, PETER - ARS-UCB PLNT GENE EXP CTR

Submitted to: Plant Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2004
Publication Date: 6/1/2004
Citation: Tepperman, J.M., Hudson, M., Khanna, R., Zhu, T., Chang, S.H., Wang, X., Quail, P.H. 2004. Expression profiling of phyB mutant demonstrates substantial contribution of other phytochromes to red-light-regulated gene expression during seedling de-etiolation. Plant Journal 38(5)775.

Interpretive Summary: Different Arabidopsis phytochrome (phy) family members (phyA through phyE) display differential photosensory and/or physiological functions in regulating growth and developmental responses to light signals. To identify the genes regulated by phyB in response to continuous monochromatic red light (Rc) during the induction of seedling de-etiolation, we have performed time-course, microarray-based expression profiling of wild type (WT) and phyB null mutants. Comparison of the observed expression patterns with those induced by continuous monochromatic far-red light (FRc; perceived exclusively by phyA) in WT and phyA null-mutant seedlings suggests early convergence of the FRc and Rc photosensory pathways to control a largely common transcriptional network. phyB mutant seedlings retain a surprisingly high level of responsiveness to Rc for the majority of Rc-regulated genes on the microarray, indicating that one or more other phys have a major role in regulating their expression. Combined with the robust visible morphogenic phenotype of the phyB mutant in Rc, these data suggest that different members of the phy family act in organ-specific fashion in regulating seedling de-etiolation. Specifically, phyB appears to be the dominant, if not exclusive, photoreceptor in regulating a minority population of genes involved in suppression of hypocotyl cell elongation in response to Rc signals. By contrast, this sensory function is apparently shared by one or more other phys in regulating the majority Rc-responsive gene set involved in other important facets of the de-etiolation process in the apical region, such as cotyledon cell expansion.

Technical Abstract: Different Arabidopsis phytochrome (phy) family members (phyA through phyE) display differential photosensory and/or physiological functions in regulating growth and developmental responses to light signals. To identify the genes regulated by phyB in response to continuous monochromatic red light (Rc) during the induction of seedling de-etiolation, we have performed time-course, microarray-based expression profiling of wild type (WT) and phyB null mutants. Comparison of the observed expression patterns with those induced by continuous monochromatic far-red light (FRc; perceived exclusively by phyA) in WT and phyA null-mutant seedlings suggests early convergence of the FRc and Rc photosensory pathways to control a largely common transcriptional network. phyB mutant seedlings retain a surprisingly high level of responsiveness to Rc for the majority of Rc-regulated genes on the microarray, indicating that one or more other phys have a major role in regulating their expression. Combined with the robust visible morphogenic phenotype of the phyB mutant in Rc, these data suggest that different members of the phy family act in organ-specific fashion in regulating seedling de-etiolation. Specifically, phyB appears to be the dominant, if not exclusive, photoreceptor in regulating a minority population of genes involved in suppression of hypocotyl cell elongation in response to Rc signals. By contrast, this sensory function is apparently shared by one or more other phys in regulating the majority Rc-responsive gene set involved in other important facets of the de-etiolation process in the apical region, such as cotyledon cell expansion.