Gene profiling of the red light signalling pathways in roots

• Published in: Journal of experimental botany 2006-09, Vol.57 (12), p.3217-3229
• Main Authors: Molas, Maria Lia, Kiss, John Z, Correll, Melanie J
• Format: Article
• Language: English
• Subjects: aerial parts; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - radiation effects; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; ATP-Binding Cassette Transporters - genetics; ATP-Binding Cassette Transporters - metabolism; biochemical pathways; Biological and medical sciences; blue light; Cell physiology; Chloroplasts; Chloroplasts - genetics; Chloroplasts - metabolism; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Profiling; Gene expression regulation; Gene Expression Regulation, Plant - radiation effects; gene profiling; Genes; Light; microarray; microarray technology; Models, Biological; Molecular and cellular biology; Oligonucleotide Array Sequence Analysis; Phenylalanine - metabolism; phenylpropanoids; photomorphogenesis; Phototropism; Phytochrome B - genetics; Phytochrome B - metabolism; Plant cells; plant development; plant growth substances; Plant roots; Plant Roots - genetics; Plant Roots - metabolism; Plant Roots - radiation effects; Plants; plastids; Plastids - genetics; Plastids - metabolism; Polymerase Chain Reaction; red light; Research Papers; root hairs; root systems; roots; Seedlings; Signal transduction; Signal Transduction - genetics; temporal variation; Up regulation
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erl086

Red light, acting through the phytochromes, controls numerous aspects of plant development. Many of the signal transduction elements downstream of the phytochromes have been identified in the aerial portions of the plant; however, very few elements in red-light signalling have been identified specifically for roots. Gene profiling studies using microarrays and quantitative Real-Time PCR were performed to characterize gene expression changes in roots of Arabidopsis seedlings exposed to 1 h of red light. Several factors acting downstream of phytochromes in red-light signalling in roots were identified. Some of the genes found to be differentially expressed in this study have already been characterized in the red-light-signalling pathway for whole plants. For example, PHYTOCHROME KINASE 1 (PKS1), LONG HYPOCOTYL 5 (HY5), EARLY FLOWERING 4 (ELF4), and GIGANTEA (GI) were all significantly up-regulated in roots of seedlings exposed to 1 h of red light. The up-regulation of SUPPRESSOR OF PHYTOCHROME A RESPONSES 1 (SPA1) and CONSTITUTIVE PHOTOMORPHOGENIC 1-like (COP1-like) genes suggests that the PHYA-mediated pathway was attenuated by red light. In addition, genes involved in lateral root and root hair formation, root plastid development, phenylpropanoid metabolism, and hormone signalling were also regulated by exposure to red light. Interestingly, members of the RPT2/NPH3 (ROOT PHOTOTROPIC 2/NON PHOTOTROPIC HYPOCOTYL 3) family, which have been shown to mediate blue-light-induced phototropism, were also differentially regulated in roots in red light. Therefore, these results suggest that red and blue light pathways interact in roots of seedlings and that many elements involved in red-light-signalling found in the aerial portions of the plant are differentially expressed in roots within 1 h of red light exposure.