Translocation of cytoplasm and nucleus to fungal penetration sites is associated with depolymerization of microtubules and defence gene activation in infected, cultured parsley cells.
We describe a novel system of reduced complexity for analysing molecular plant-fungus interactions. The system consists of suspension-cultured parsley (Petroselinum crispum) cells infected with a phytopathogenic fungus (Phytophthora infestans) which adheres to a coated glass plate and thus immobilizes the plant cells for live microscopy. Conventional light and electron microscopy as well as time-lapse video microscopy confirmed the virtual identity of fungal infection structures and of several characteristic early plant defence reactions in the cultured cells and whole-plant tissue. Using this new system to approach previously unresolved questions, we made four major discoveries: (i) rapid translocation of plant cell cytoplasm and nucleus to the fungal penetration site was associated with local depolymerization of the microtubular network; (ii) the directed translocation was dependent on intact actin filaments; (iii) a typical plant defence-related gene was activated in the fungus-invaded cell; and (iv) simultaneous activation of this gene in adjacent, non-invaded cells did not require hypersensitive death of the directly affected cell.
Max-Planck-Institut für Züchtungsforschung, Abteilung Biochemie, Köln, Germany.
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P
Gross
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C
Julius
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E
Schmelzer
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K
Hahlbrock
D000199:Actins / Q000378:metabolism; D016923:Cell Death; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism*; D015870:Gene Expression; D017343:Genes, Plant; D008854:Microscopy, Electron; D008870:Microtubules / Q000378:metabolism*; D010838:Phytophthora / Q000302:isolation & purification / Q000502:physiology* / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000235:genetics / Q000382:microbiology* / Q000648:ultrastructure; D014743:Videotape Recording
D000199:Actins; D010940:Plant Proteins; C053376:pathogenesis-related proteins, plant