Schlüsselwörter
(Englisch)
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Population genetics; microsatellites; coalescent; forest ecosystems; nurseries; homothallic; species complex
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Forschungsprogramme
(Englisch)
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COST-Action FP0801 - Established and Emerging Phytophthora: Increasing Threats to Woodland and Forest Ecosystems in Europe
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Kurzbeschreibung
(Englisch)
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Within the cosmopolitan plant pathogenic species Phytophthora citricola, high levels of morphological and molecular variation were previously observed. Recently, DNA analyses revealed that the P. citricola complex actually includes four species, namely P. multivora, P. plurivora, P. citricola I, and P. citricola sensu strictu, which show different geographic distributions and host ranges. Unfortunately, because of the lack of neutral, species-specific genetic markers, detailed knowledge on the population genetic structure and possible path-ways of spread of these four Phytophthora species is still missing. In this research project, we aim (1) to develop and characterize polymorphic microsatellite markers for analysing the genetic structure of the four Phytophthora species in the P. citricola complex, (2) to analyse worldwide population structure and pathways of spread of P. multivora, P. plurivora, P. citricola I, and P. citricola ss. using the microsatellites newly developed, and (3) to investigate the demographic history of P. plurivora in Europe by using coalescent-based methods. Besides providing new genetic markers for additional studies on P. multivora, P. plurivora, P. citricola I, and P. citricola ss., results of this project will help to better understand the worldwide population genetic structure and dynamics of closely-related Phytophthora species.
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Partner und Internationale Organisationen
(Englisch)
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AT, BE, BG, CH, CZ, DE, DK, EL, ES, FI, FR, HU, IE, IT, LT, LV, MK, NL, NO, PL, PT, RO, RS, SE, SI, SK, TR, UK
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Abstract
(Englisch)
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The objectives of our research project are: (1) to develop and characterize polymorphic microsatellite markers for analysing the genetic structure of the four plant pathogenic Phytophthora species in the former P. citricola complex, i.e. P. plurivora, P. multivora, P. pini, and P. citricola s.s.; (2) to investigate the worldwide population structure and pathways of spread of these four species by using the developed microsatellites; and (3) to investigate the demographic history of P. plurivora in Europe by using coalescent-based methods. During the first year of the project, most activities focused on the objectives (1) and (2). As planned, microsatellites were developed for all four Phytophthora species targeted. Their polymorphism was tested on a subset of isolates for P. plurivora (12 polymorphic loci), P. multivora (17 polymorphic loci), and P. pini (8 polymorphic loci) but not for P. citricola s.s. (not enough isolates avaliable so far). About 600 isolates of P. citricola s.l. could be put together at the WSL institute thanks to the help of the international Phytophthora scientific community. Species identification based on sequencing of the beta tubulin gene showed that P. plurivora was the most frequent species (about 400 isolates) and was followed by P. pini (120), P. multivora (40), and P. citricola s.s. (7). For population genetic analyses, all P. plurivora, P. pini, and P. multivora isolates were genotyped at the polymorphic microsatellite loci previously developed. The raw data will be analysed during the second year of the project. Potential genes for coalescent analyses have been selected based on previous studies. These genes are being sequenced for a subset of P. plurivora genotypes which was selected based on their belonging to different gene pools. The sequences obtained will be used to depict the worldwide demographic history of P. plurivora.
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Datenbankreferenzen
(Englisch)
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Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. +41 31 322 74 82 Swiss Project-Number: C10.0129
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