Induction of UDP-glucose:salicylic acid glucosyltransferase activity in tobacco mosaic virus-inoculated tobacco (Nicotiana tabacum) leaves

• Published in: Plant physiology (Bethesda) 1993-04, Vol.101 (4), p.1375-1380
• Main Authors: Enyedi, A.J, Raskin, I
• Format: Article
• Language: English
• Subjects: 550200 - Biochemistry; ACIDE SALICYLIQUE; ACIDO SALICILICO; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Agronomy. Soil science and plant productions; ALDEHYDES; ANTI-INFECTIVE AGENTS; ANTIBIOTICS; BASIC BIOLOGICAL SCIENCES; Biological and medical sciences; CARBOHYDRATES; CARBOXYLIC ACIDS; Coumaric acids; CYCLOHEXIMIDE; DRUGS; ENZYMES; FEUILLE; Fundamental and applied biological sciences. Psychology; FUNGICIDES; GLICOSILTRANSFERASAS; GLUCOSE; GLUCOSIDASE; GLYCOSYL HYDROLASES; GLYCOSYLTRANSFERASE; HEXOSES; HOJAS; HYDROLASES; HYDROXY ACIDS; Hydroxybenzoic acids; Inductive reasoning; Inoculation; Leaves; MAGNOLIOPHYTA; MAGNOLIOPSIDA; MICROORGANISMS; MONOSACCHARIDES; NICOTIANA; NICOTIANA TABACUM; O-GLYCOSYL HYDROLASES; Oats; ORGANIC ACIDS; ORGANIC COMPOUNDS; PARASITES; PATHOGENS; Pathology. Damages, economic importance; PESTICIDES; Phytopathology. Animal pests. Plant and forest protection; Plant cells; Plant viruses and viroids; Plant-Microbe Interactions; PLANTS; PROTEINS; RESPONSE MODIFYING FACTORS; SACCHARIDES; SALICYLIC ACID; Systemic acquired resistance; TOBACCO; TOBACCO MOSAIC VIRUS; TOBAMOVIRUS DEL MOSAICO DEL TABACO; TOBAMOVIRUS MOSAIQUE DU TABAC; VIRUSES
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.101.4.1375

Salicylic acid (SA) is a putative signal that activates plant resistance to pathogens. SA levels increase systemically following the hypersensitive response produced by tobacco mosaic virus (TMV) inoculation of tobacco (Nicotiana tabacum L. cv Xanthi-nc) leaves. The SA increase in the inoculated leaf coincided with the appearance of a beta-glucosidase-hydrolyzable SA conjugate identified as beta-O-D-glucosylsalicylic acid (GSA). SA and GSA accumulation in the TMV-inoculated leaf paralleled the increase in the activity of a UDP-glucose:salicylic acid 3-O-glucosyltransferase (EC 2.4.1.35) (beta-GTase) capable of converting SA to GSA. Healthy tissues had constitutive beta-GTase activity of 0.076 milliunits g(-1) fresh weight. This activity started to increase 48 h after TMV inoculation, reaching its maximum (6.7-fold induction over the basal levels) 72 h after TMV inoculation. No significant GSA or elevated beta-GTase activity could be detected in the healthy leaf immediately above the TMV-inoculated leaf. The effect of TMV inoculation on the beta-GTase and GSA accumulation could be duplicated by infiltrating tobacco leaf discs with SA at the levels naturally produced in TMV-inoculated leaves (2.7-27.0 micrograms g(-1) fresh weight). Pretreatment of leaf discs with the protein synthesis inhibitor cycloheximide inhibited the induction of beta-GTase by SA and prevented the formation of GSA. Of 12 analogs of SA tested, only 2,6-dihydroxybenzoic acid induced beta-GTase activity