Differential activation of H+-ATPase genes by an arbuscular mycorrhizal fungus in root cells of transgenic tobacco.
In arbuscular mycorrhizas, H+-ATPase is active in the plant membrane around arbuscules but absent from plant mutants defective in arbuscule development (Gianinazzi-Pearson et al. 1995, Can J Bot 73: S526-S532). The proton-pumping H+-ATPase is encoded by a family of genes in plants. Immunocytochemical studies and promoter-gusA fusion assays were performed in transgenic tobacco (Nicotiana tabacum L.) to determine whether the periarbuscular enzyme activity results from de-novo activation of plant genes by an arbuscular mycorrhizal fungus. The H+-ATPase protein was localized in the plant membrane around arbuscule hyphae. The enzyme was absent from non-colonized cortical cells. Regulation of seven H+-ATPase genes (pma) was compared in non-mycorrhizal and mycorrhizal roots by histochemical detection of beta-glucuronidase (GUS) activity. Two genes (pma2, pma4) were induced in arbuscule-containing cells of mycorrhizal roots but not in non-mycorrhizal cortical tissues or senescent mycorrhiza. It is concluded that de-novo H+-ATPase activity in the periarbuscular membrane results from selective induction of two H+-ATPase genes, which can have diverse roles in plant-fungal interactions at the symbiotic interface.
Gianinazzi-Pearson
V
V
Laboratoire de Phytoparasitologie INRA/CNRS, Centre de Microbiologie du Sol et de l'Environnement-Institut National de la Recherche Agronomique, Dijon, France. vivienne.gianninazzi-pearson@epoisses.inra.fr
Arnould
C
C
Oufattole
M
M
Arango
M
M
Gianinazzi
S
S
D003594:Cytoplasmic Granules / Q000201:enzymology / Q000648:ultrastructure; D005658:Fungi / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D018517:Plant Roots / Q000166:cytology / Q000201:enzymology / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000382:microbiology; D010947:Plants, Toxic; D006180:Proton-Translocating ATPases / Q000032:analysis / Q000235:genetics*; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics* / Q000382:microbiology
D006180:Proton-Translocating ATPases