UV-B signaling pathways with different fluence-rate response profiles are distinguished in mature Arabidopsis leaf tissue by requirement for UVR8, HY5, and HYH

Brown, B.A. and Jenkins, G.I. (2008) UV-B signaling pathways with different fluence-rate response profiles are distinguished in mature Arabidopsis leaf tissue by requirement for UVR8, HY5, and HYH. Plant Physiology, 146(2), pp. 576-588. (doi:10.1104/pp.107.108456)

Brown, B.A. and Jenkins, G.I. (2008) UV-B signaling pathways with different fluence-rate response profiles are distinguished in mature Arabidopsis leaf tissue by requirement for UVR8, HY5, and HYH. Plant Physiology, 146(2), pp. 576-588. (doi:10.1104/pp.107.108456)

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Publisher's URL: http://dx.doi.org/10.1104/pp.107.108456

Abstract

UV-B signaling is an important but poorly understood aspect of light responsiveness in plants. Arabidopsis (Arabidopsis thaliana) UV RESISTANCE LOCUS8 (UVR8) is a recently identified UV-B-specific signaling component that regulates UV-protective responses. Using the uvr8 mutant, we defined genetically distinct UVR8-dependent and UVR8-independent pathways that stimulate different sets of genes in mature Arabidopsis leaf tissue. Both pathways operate at 1 mu mol m(-2) s(-1) UV-B and above, but the UVR8-dependent pathway is able to stimulateUV-protective genes even in response to 0.1 mu mol m(-2) s(-1) UV-B. Both pathways function in mutants lacking phytochromes, cryptochromes, or phototropins. Genes encoding the ELONGATED HYPOCOTYL5 (HY5) and HY5 HOMOLOG (HYH) transcription factors are induced at low UV-B fluence rates (0.1 mu mol m(-2) s(-1)). Experiments with hy5 and hyh mutants reveal that both these factors mediate responses of the UVR8-dependent pathway, acting with partial or complete redundancy to stimulate expression of particular genes. Furthermore, evidence is presented that all UVR8 pathway genes are likely to be regulated by HY5/HYH and that these transcription factors do not mediate UV-B responses independent of UVR8. Finally, we highlight the functions of HY5 and HYH in UV protection and show that HY5 plays the more critical role. This research provides evidence that, in UV-B signaling, UVR8, HY5, and HYH act together in a photoregulatory pathway and demonstrates a new role for HYH in UV-B responses

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Jenkins, Professor Gareth
Authors: Brown, B.A., and Jenkins, G.I.
Subjects:Q Science > QK Botany
Q Science > QP Physiology
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Plant Physiology
ISSN:0032-0889

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
419341Characterisation of a UVB specific signalling pathwayGareth JenkinsBiotechnology and Biological Sciences Research Council (BBSRC)BB/D019281/1Institute of Molecular Cell and Systems Biology