Physiological changes of Fagus sylvatica seedlings infected with Phytophthora citricola and the contribution of its elicitin "citricolin" to pathogenesis.
Beech seedlings were infected with the root rot pathogen Phytophthora citricola to study its impact on leaf physiology and water status. Net photosynthesis rate decreased two days after inoculation in infected seedlings. In contrast, electron quantum yield of photosystem II, leaf water potential, and total water consumption were only slightly impaired until 6 dpi. At the same time, wilt symptoms occurred on leaves. These results indicate the involvement of a mobile signal triggering the early changes in leaf physiology by root infection. As the elicitin gene of P. citricola was induced during root infection, we purified and characterised the elicitin protein and tested its ability to change leaf physiological parameters of beech and tobacco plants. P. citricola produced a single acidic elicitin (citricolin), which caused necrosis and decreased gas exchange of tobacco leaves. Furthermore, it induced an oxidative burst in tobacco cell suspension culture. However, none of these effects were observed in beech.
Fleischmann
F
F
Section Pathology of Woody Plants, Technische Universität München, Am Hochanger 13, 85354 Freising-Weihenstephan, Germany. fleischmann@wzw.tum.de
Koehl
J
J
Portz
R
R
Beltrame
A B
AB
Osswald
W
W
D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D000595:Amino Acid Sequence; D002478:Cells, Cultured; D029964:Fagus / Q000382:microbiology* / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D010838:Phytophthora / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000187:drug effects / Q000382:microbiology; D018526:Plant Transpiration; D011506:Proteins; D016897:Respiratory Burst; D036226:Seedlings / Q000382:microbiology / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014026:Nicotiana / Q000166:cytology / Q000187:drug effects; D014867:Water / Q000378:metabolism
D020418:Algal Proteins; D011506:Proteins; C085101:elicitin, Phytophthora; D014867:Water