Integrated Temporal Regulation of the Photorespiratory Pathway. Circadian Regulation of Two Arabidopsis Genes Encoding Serine Hydroxymethyltransferase

• Published in: Plant physiology (Bethesda) Vol. 123; no. 1; pp. 381 - 391
• Main Authors: McClung, C. Robertson, Meier Hsu, Painter, Janet E., Gagne, Jennifer M., Sharon D. Karlsberg, Salomé, Patrice A.
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.05.2000; American Society of Plant Biologists
• Subjects: Amino Acid Sequence; Amino acids; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis - physiology; Arabidopsis thaliana; Biological and medical sciences; Circadian rhythms; Complementary DNA; Fundamental and applied biological sciences. Psychology; Gene expression; Gene expression regulation; Gene Expression Regulation, Enzymologic - radiation effects; Gene Expression Regulation, Plant - radiation effects; Genes; Genetics, Genomics, and Molecular Evolution; Glycine Hydroxymethyltransferase - chemistry; Glycine Hydroxymethyltransferase - genetics; Introns; Light; Messenger RNA; Metabolism; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Multigene Family; Photosynthesis; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; Plant roots; Plants; RNA; RNA, Messenger - genetics; RNA, Messenger - metabolism; Seedlings; Sequence Homology, Amino Acid; Serine hydroxymethyltransferase; SHM1 gene; SHM4 gene; Glycine hydroxymethyltransferase; Enzyme; Transferases; Circadian rhythm; Gene expression; Time variation; Arabidopsis thaliana; Regulation(control); Cruciferae; Photorespiration; Dicotyledones; Angiospermae; Spermatophyta; Experimental plant
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.123.1.381

The photorespiratory pathway is comprised of enzymes localized within three distinct cellular compartments: chloroplasts, peroxisomes, and mitochondria. Photorespiratory enzymes are encoded by nuclear genes, translated in the cytosol, and targeted into these distinct subcellular compartments. One likely means by which to regulate the expression of the genes encoding photorespiratory enzymes is coordinated temporal control. We have previously shown in Arabidopsis that a circadian clock regulates the expression of the nuclear genes encoding both chloroplastic (Rubisco small subunit and Rubisco activase) and peroxisomal (catalase) components of the photorespiratory pathway. To determine whether a circadian clock also regulates the expression of genes encoding mitochondrial components of the photorespiratory pathway, we characterized a family of Arabidopsis serine hydroxymethyltransferase (SHM) genes. We examined mRNA accumulation for two of these family members, including one probable photorespiratory gene (SHM1) and a second gene expressed maximally in roots (SHM4), and show that both exhibit circadian oscillations in mRNA abundance that are in phase with those described for other photorespiratory genes. In addition, we show that SHM1 mRNA accumulates in light-grown seedlings, although this response is probably an indirect consequence of the induction of photosynthesis and photorespiration by illumination.