Een ontmoeting met de Nederlanders: populatiegenetica van Phytophthora infestans in Nederland gedurende het laatste decennium

Een set van meer dan duizend P. infestans-isolaten afkomstig van aardappelproductievelden en onderzoeksvelden werd verzameld in de periode 2000-2009. De genetische diversiteit van de Nederlandse populatie werd bepaald. De resultaten laten zien dat elk jaar als gevolg van de seksuele cyclus een groot aantal nieuwe genotypen wordt gevormd, waarvan er slechts enkele zo succesvol zijn dat ze lokaal of regionaal een epidemie veroorzaken

Onderzoek naar de resistentie van de bruine rat in Nederland - 2012

Development and application of a quick test for resistance of brown rats against rodenticides

Population dynamics of Phytophthora infestans in the Netherlands reveals expansion and spread of dominant clonal lineages and virulence in sexual offspring

For a comprehensive survey of the structure and dynamics of the Dutch Phytophthora infestans population, 652 P. infestans isolates were collected from commercial potato fields in the Netherlands during the 10-year period 2000–2009. Genotyping was performed using 12 highly informative microsatellite markers and mitochondrial haplotypes. In addition, for each isolate, the mating type was determined. STRUCTURE analysis grouped the 322 identified genotypes in three clusters. Cluster 1 consists of a single clonal lineage NL-001, known as “Blue_13”; all isolates in this cluster have the A2 mating type and the Ia mitochondrial haplotype. Clusters 2 and 3 display a more elaborate substructure containing many unique genotypes. In Cluster 3, several distinct clonal lineages were also identified. This survey witnesses that the Dutch population underwent dramatic changes in the 10 years under study. The most notable change was the emergence and spread of A2 mating type strain NL-001 (or “Blue_13”). The results emphasize the importance of the sexual cycle in generating genetic diversity and the importance of the asexual cycle as the propagation and dispersal mechanism for successful genotypes. Isolates were also screened for absence of the Avrblb1/ipiO class I gene, which is indicative for virulence on Rpi-blb1. This is also the first report of Rpi-blb1 breakers in the Netherlands. Superimposing the virulence screening on the SSR genetic backbone indicates that lack the Avrblb1/ipiO class I gene only occurred in sexual progeny. So far, the asexual spread of the virulent isolates identified has been limited

Schimmels in water opsporen

Het is een heel gevoelige opsporingsmethode die zeer specifiek kan worden uitgevoerd. Er wordt gewerkt aan een juiste vaststelling van besmetting van water door Phytophthora fragariae in aardbei en Phytophthora cryptogea in witlo

Swab de bijenkast

In de laatste anderhalf jaar heeft vrijweel iedereen kennis gemaakt met de swab, het speciale wattenstaafje waarmee testmateriaal wordt afgenomen. Wij hebben onderzoek gedaan naar het gebruik van swabs, om hiermee ziekteverwekkers van de honingbij aan te tonen. de swab past niet in de monddelen van de bij, maar wel in de bijenkast. Deze bemonsteringsmethode is eenvoudig en niet-destructief

Detection of small hive beetle: frass as a source of DNA

Current diagnostic techniques for the detection of the small hive beetle (SHB), Aethina tumida are limitedly available and not cost effective. More sensitive pragmatic methods are preferred for early detection. To improve diagnostics, we focused on sampling techniques for SHB frass, as an indicator for SHB presence in a honey bee colony. In this study, we successfully tested a novel approach of employing swab sample collection of frass for real-time PCR detection of SH

Schimmels in water opsporen

Het is een heel gevoelige opsporingsmethode die zeer specifiek kan worden uitgevoerd. Er wordt gewerkt aan een juiste vaststelling van besmetting van water door Phytophthora fragariae in aardbei en Phytophthora cryptogea in witlo

Improved real-time PCR assay for detection of the quarantine potato pathogen, Synchytrium endobioticum, in zonal centrifuge extracts from soil and in plants

Real-time PCR was used for quantitative detection of the potato pathogen, Synchytrium endobioticum, in different substrates: zonal centrifuge extracts, warts and different plant parts of potato. Specific primers and a TaqMan probe, designed from the internal transcribed spacer region of the multi-copy rDNA gene were tested in extracts from artificially and naturally infested soil. Co-amplification of target DNA along with an internal competitor DNA fragment made the diagnostic assay more reliable by guarding against false negative results. A calibrations curve was created by spiking zonal centrifuge fractions of clean soil samples with a dilution series of winter spores. The Taqman assay was also performed on infected potato plant material (stolons) along with the detection of the cytochrome oxidase gene as a potato endogenous control. Sensitivity of the TaqMan assay was improved at least 100-fold and proved to be reliable for accurate diagnosis of the disease