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P hytophthora diversity and the population structure of P hytophthora ramorum in S wiss ornamental nurseries
Author(s) -
Prospero S.,
Vercauteren A.,
Heungens K.,
Belbahri L.,
Rigling D.
Publication year - 2013
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.12027
Subject(s) - phytophthora ramorum , biology , population , ornamental plant , outbreak , microsatellite , oomycete , passerine , botany , zoology , pathogen , genetics , demography , virology , allele , phytophthora , sociology , gene
Invasive oomycete pathogens have been causing significant damage to native ecosystems worldwide for over a century. A recent well‐known example is P hytophthora ramorum , the causal agent of sudden oak death, which emerged in the 1990s in E urope and N orth A merica. In E urope, this pathogen is mainly restricted to woody ornamentals in nurseries and public greens, while severe outbreaks in the wild have only been reported in the UK . This study presents the results of the P . ramorum survey conducted in Swiss nurseries between 2003 and 2011. In all 120 nurseries subjected to the plant passport system, the main P . ramorum hosts were visually checked for above ground infections. P hytophthora species were isolated from tissue showing symptoms and identified on the basis of the morphological features of the cultures and sequencing of the ribosomal ITS region. P hytophthora was detected on 125 plants (66 V iburnum , 58 R hododendron and one P ieris ). P hytophthora ramorum was the most frequent species (59·2% of the plants), followed by P . plurivora , P . cactorum , P . citrophthora , P . cinnamomi , P . cactorum/P. hedraiandra , P . multivora and P . taxon PgChlamydo. The highest incidence of P . ramorum was observed on V iburnum × bodnantense . Microsatellite genotyping showed that the Swiss P . ramorum population is highly clonal and consists of seven genotypes (five previously reported in Europe, two new), all belonging to the European EU 1 clonal lineage. It can therefore be assumed that P . ramorum entered S witzerland through nursery trade. Despite sanitation measures, repeated P . ramorum infections have been recorded in seven nurseries, suggesting either reintroduction or unsuccessful eradication efforts.