Pleiotropic effects of tobacco-mosaic-virus movement protein on carbon metabolism in transgenic tobacco plants

• Published in: Planta 1995-08, Vol.197 (1), p.118-126
• Main Authors: Olesinski, A.A, Lucas, W.J, Galun, E, Wolf, S. (Hebrew Univ., Rehovot (Israel). Faculty of Agriculture, Dept. of Vegetable Crops)
• Format: Article
• Language: English
• Subjects: ALMIDON; AMIDON; AZUCAR; Biological and medical sciences; CARBOHIDRATOS; CARBOHYDRATES; CARBON; CARBONE; CARBONO; CYTOPLASMIC ORGANELLES; ECHANGE GAZEUX; EXPRESION GENICA; EXPRESSION DES GENES; FEUILLE; FLOEMA; FOTOSINTESIS; FRUCTOSA; FRUCTOSE; Fundamental and applied biological sciences. Psychology; GAS EXCHANGE; GENE EXPRESSION; GLUCIDE; GLUCOSA; GLUCOSE; HOJAS; INTERCAMBIO DE GASES; Kohlenstoffwechsel; LEAVES; MESOFILO; MESOPHYLL; MESOPHYLLE; MUTANT; MUTANTES; MUTANTS; NICOTIANA TABACUM; NUTRICION DE LAS PLANTAS; NUTRITION DES PLANTES; ORGANITE CELLULAIRE; ORGANULOS CITOPLASMICOS; Pathology. Damages, economic importance; Pflanzenbau; Pflanzenphysiologie; Pflanzenzuechtung; PHLOEM; PHLOEME; PHOTOSYNTHESE; PHOTOSYNTHESIS; Phytopathology. Animal pests. Plant and forest protection; PLANT NUTRITION; Plant viruses and viroids; PLANTAS TRANSGENICAS; PLANTE TRANSGENIQUE; Plants; Plasmodesma; Plasmodesmata; Pleiotropie; PROTEINAS; PROTEINE; PROTEINS; Radioactive decay; radioaktive Markierung; Radiocarbon; SACCHAROSE; STARCH; Starches; SUCRE; SUCROSA; SUCROSE; SUGAR; Sugars; TECHNIQUE DES TRACEURS; TECNICAS DE TRAZADORES; TEMPERATURA; TEMPERATURE; TOBACCO MOSAIC TOBAMOVIRUS; Tobacco mosaic virus; TOBAMOVIRUS DEL MOSAICO DEL TABACO; TOBAMOVIRUS MOSAIQUE DU TABAC; TRACER TECHNIQUES; TRANSGENIC PLANTS
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/BF00239947

Transgenic tobacco (Nicotiana tabacum L. cv. Xanthi) plants expressing wild-type or mutant forms of the 30-kDA movement protein of tobacco mosaic virus (TMV-MP) were employed to study the effects of the TMV-MP on carbon metabolism in source leaves. Fully expanded source leaves of transgenic plants expressing the TMV-MP were found to retain more newly fixed 14C compared with control plants. Analysis of 14C-export from young leaves of TMV-MP plants, where the MP is yet to influence plasmodesmal size exclusion limit, indicated a similar pattern, in that daytime 14C export was slower in TMV-MP plants as compared to equivalent-aged leaves on control plants. Pulse-chase experiments were used to monitor radioactivity present in the different carbohydrate fractions, at specified intervals following 14CO2 labeling. These studies established that the TMV-MP can cause a significant adjustment in short-term 14C-photosynthate storage and export. That these effects of the TMV-MP on carbon metabolism and phloem function were not attributable to the effect of this protein on plasmodesmal size exclusion limits, per se, was established using transgenic tobacco plants expressing temperature-sensitive and C-terminal deletion mutant forms of the TMV-MP. Collectively, these studies establish the pleiotropic nature of the TMV-MP in transgenic tobacco, and the results are discussed in terms of potential sites of interaction between the TMV-MP and endogenous processes involved in regulating carbon metabolism and export.