Targeted modification of homogalacturonan by transgenic expression of a fungal polygalacturonase alters plant growth

• Published in: Plant physiology (Bethesda) Vol. 135; no. 3; pp. 1294 - 1304
• Main Authors: Capodicasa, C, Vairo, D, Zabotina, O, McCartney, L, Caprari, C, Mattei, B, Manfredini, C, Aracri, B, Benen, J, Knox, J.P
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01.07.2004; American Society of Plant Physiologists
• Subjects: Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis thaliana; Aspergillus niger; Aspergillus niger - enzymology; Base Sequence; Biochemical Processes and Macromolecular Structures; Biological and medical sciences; Cell lines; Cell walls; chemical composition; DNA Primers; dwarfing; enzyme activity; Enzymes; Epitopes; Fundamental and applied biological sciences. Psychology; fungal proteins; galacturonic acid; gene expression regulation; homogalacturonan; molecular sequence data; Monoclonal antibodies; Nicotiana - genetics; Nicotiana - growth & development; Nicotiana - metabolism; Nicotiana tabacum; nucleotide sequences; Pectins - metabolism; Phenotypes; phenotypic variation; plant anatomy; Plant growth; Plant growth. Development of the storage organs; plant morphology; Plant physiology and development; Plant Stems - enzymology; Plants; Plants, Genetically Modified; polygalacturonase; Polygalacturonase - genetics; Polygalacturonase - isolation & purification; Polygalacturonase - metabolism; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Stems; tobacco; transgenes; Transgenic plants; Vegetative apparatus, growth and morphogenesis. Senescence; Enzyme; Growth; Pectin; Polygalacturonase; Gene expression; Nicotiana tabacum; Cell wall; Dicotyledones; Glycosidases; Angiospermae; Hydrolases; Spermatophyta; Transgenic plant; Solanaceae; O-Glycosidases
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.104.042788

Pectins are a highly complex family of cell wall polysaccharides comprised of homogalacturonan (HGA), rhamnogalacturonan I and rhamnogalacturonan II. We have specifically modified HGA in both tobacco (Nicotiana tabacum) and Arabidopsis by expressing the endopolygalacturonase II of Aspergillus niger (AnPGII). Cell walls of transgenic tobacco plants showed a 25% reduction in GalUA content as compared with the wild type and a reduced content of deesterified HGA as detected by antibody labeling. Neutral sugars remained unchanged apart from a slight increase of Rha, Ara, and Gal. Both transgenic tobacco and Arabidopsis were dwarfed, indicating that unesterified HGA is a critical factor for plant cell growth. The dwarf phenotypes were associated with AnPGII activity as demonstrated by the observation that the mutant phenotype of tobacco was completely reverted by crossing the dwarfed plants with plants expressing PGIP2, a strong inhibitor of AnPGII. The mutant phenotype in Arabidopsis did not appear when transformation was performed with a gene encoding AnPGII inactivated by site directed mutagenesis.