Regulation of tobacco acetolactate synthase gene expression

• Published in: Plant physiology (Bethesda) Vol. 102; no. 3; pp. 1009 - 1018
• Main Authors: Keeler, S.J, Sanders, P, Smith, J.K, Mazur, B.J
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.07.1993
• Subjects: Acetolactate Synthase - biosynthesis; Acetolactate Synthase - genetics; Alleles; ANTERA; ANTHERE; ARN MENSAJERO; ARN MESSAGER; Base Sequence; Biological and medical sciences; COROLA; COROLLE; Enzymes; EXPRESION GENICA; EXPRESSION DES GENES; FEUILLE; FLEUR; FLORES; Fundamental and applied biological sciences. Psychology; GENE; Gene expression; Gene Expression Regulation, Enzymologic; GENES; Genes, Plant; Genetic hybridization; GENETICA; GENETIQUE; GINECEO; GYNECEE; HOJAS; In Situ Hybridization; Leaves; LIASAS; LYASE; Messenger RNA; Metabolism; Molecular Biology and Gene Regulation; Molecular Sequence Data; Nicotiana - cytology; Nicotiana - enzymology; Nicotiana - genetics; NICOTIANA TABACUM; Plant physiology and development; Plant roots; Plants; Plants, Toxic; RACINE; RAICES; RNA; RNA, Messenger - analysis; RNA, Messenger - biosynthesis; RNA, Messenger - metabolism; Sequence Homology, Nucleic Acid; Stems; TALLO; TEJIDOS VEGETALES; TIGE; TISSU VEGETAL; Transcription, Genetic; Plant tissue; Transcription; Enzyme; Lyases; Biosynthesis; Cytochemistry; Gene expression; Nicotiana tabacum; Oxo-acid-lyases; Carbon-carbon lyases; Dicotyledones; Aminoacid; Angiospermae; Acetolactate synthase; Spermatophyta; Developmental stage; Solanaceae; Localization
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.102.3.1009

Acetolactate synthase (ALS) catalyzes the first common step in the biosynthesis of isoleucine, leucine, and valine. The previous cloning of two tobacco (Nicotiana tabacum) ALS genes SurA and SurB) has allowed transcript accumulation from these genes to be monitored. mRNA blot analysis of ALS transcripts showed a message size of 2.2 kb. Quantitation of the levels of ALS messages in tobacco organs indicated that there was a 3- to 4-fold variation in the levels of expression of the ALS genes in different organs. This variability correlated with the developmental stage of the samples, with the highest levels of expression found in developing organs. In situ hybridizations of anti-mRNA probes to plant sections established that ALS messages are most prevalent in metabolically active and dividing cells of roots, stems, and floral tissue. Using RNase protection assays, the transcriptional start sites of the ALS genes were determined, and the expression levels of the two tobacco ALS genes were then followed separately. Both tobacco ALS genes are expressed in a coordinated manner in all tobacco organs examined, with the SurB gene being consistently expressed at higher levels than the SurA gene