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5 results on '"Kroon, L. P. N. M."'

2. Genetic structure and pathogenicity of populations of Phytophthora infestans from organic potato crops in France, Norway, Switzerland and the United Kingdom

Author

Flier, W. G., Kroon, L. P. N. M., Hermansen, A., van Raaij, H. M. G., Speiser, B., Tamm, L., Fuchs, J. G., Lambion, J., Razzaghian, J., Andrivon, D., Wilcockson, S., Leifert, C., Flier, W. G., Kroon, L. P. N. M., Hermansen, A., van Raaij, H. M. G., Speiser, B., Tamm, L., Fuchs, J. G., Lambion, J., Razzaghian, J., Andrivon, D., Wilcockson, S., and Leifert, C.

Abstract

Genetic variation and pathogenicity of Phytophthora infestans isolates collected from organic potato crops of the susceptible cv. Bintje and the moderately resistant cv. Santé were assessed in France, Norway, and the United Kingdom in 2001 and in Switzerland in 2001 and 2002. Population structures differed considerably between the four P. infestans populations. Those from France, Switzerland and the UK were mainly clonal populations showing restricted levels of genetic diversity, whilst those from Norway were mixed A1 and A2 mating type populations with high levels of genetic diversity, suggesting periodical sexual reproduction. Isolates collected from cv. Bintje were on average more aggressive than or comparable to isolates from cv. Santé. Race complexity varied considerably between the regional P. infestans populations, with isolates from France and Switzerland showing the highest number of virulence factors. In all pathogen samples but the French, isolates collected from cv. Santé were more complex than isolates collected from cv. Bintje. No directional selection towards increased aggressiveness towards the more resistant cultivar Santé was observed. This suggests that there is no shift towards increased levels of pathogenicity in P. infestans populations following the large-scale introduction of more resistant potato varieties in organic production systems in Europe.

Published
2007

3. Genetic structure and pathogenicity of populations of Phytophthora infestans from organic potato crops in France, Norway, Switzerland and the United Kingdom

Author

Flier, W. G., primary, Kroon, L. P. N. M., additional, Hermansen, A., additional, van Raaij, H. M. G., additional, Speiser, B., additional, Tamm, L., additional, Fuchs, J. G., additional, Lambion, J., additional, Razzaghian, J., additional, Andrivon, D., additional, Wilcockson, S., additional, and Leifert, C., additional

Published
2007
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5. Phylogenetic analysis of Phytophthora species based on mitochondrial and nuclear DNA sequences.

Author

Kroon LP, Bakker FT, van den Bosch GB, Bonants PJ, and Flier WG

Subjects
Biological Evolution, Electron Transport Complex IV classification, Electron Transport Complex IV genetics, Molecular Sequence Data, NADH Dehydrogenase classification, NADH Dehydrogenase genetics, Open Reading Frames genetics, Peptide Elongation Factor 1 classification, Peptide Elongation Factor 1 genetics, Phytophthora genetics, Sequence Analysis, DNA, Tubulin classification, Tubulin genetics, Cell Nucleus genetics, DNA classification, DNA, Mitochondrial classification, Phylogeny, Phytophthora classification
Abstract

A molecular phylogenetic analysis of the genus Phytophthora was performed, 113 isolates from 48 Phytophthora species were included in this analysis. Phylogenetic analyses were performed on regions of mitochondrial (cytochrome c oxidase subunit 1; NADH dehydrogenase subunit 1) and nuclear gene sequences (translation elongation factor 1alpha; beta-tubulin) and comparisons made to test for incongruence between the mitochondrial and nuclear data sets. The genus Phytophthora was confirmed to be monophyletic. In addition, results confirm that the classical taxonomic grouping as described by [Waterhouse (1963)] does not reflect true phylogenetic relations. Phytophthora species were redistributed into 8 clades, providing a more accurate representation of phylogenetic relationships within the genus Phytophthora. The evolution and transition of morphological, pathogenic, and reproductive traits was inferred from the cladogram generated in this study. Mating system was inferred to be a homoplasious trait, with at least eight independent transitions from homothallism to heterothallism observed.

Published
2004
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