Targeted modification of homogalacturonan by transgenic expression of a fungal polygalacturonase alters plant growth.
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.
Capodicasa
Cristina
C
Dipartimento di Biologia Vegetale e Laboratorio di Genomica Funzionale e Proteomica, Università di Roma La Sapienza, 00185 Rome, Italy.
Vairo
Donatella
D
Zabotina
Olga
O
McCartney
Lesley
L
Caprari
Claudio
C
Mattei
Benedetta
B
Manfredini
Cinzia
C
Aracri
Benedetto
B
Benen
Jacques
J
Knox
J Paul
JP
De Lorenzo
Giulia
G
Cervone
Felice
F
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D001234:Aspergillus niger / Q000201:enzymology*; D001483:Base Sequence; D017931:DNA Primers; D010368:Pectins / Q000378:metabolism*; D018547:Plant Stems / Q000201:enzymology; D030821:Plants, Genetically Modified; D011096:Polygalacturonase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
D017931:DNA Primers; D011994:Recombinant Proteins; D010368:Pectins; C400187:endopolygalacturonase II; D011096:Polygalacturonase; C003181:polygalacturonic acid