DNA fingerprinting, metalaxyl resistance and mating type determination of thePhytophthora infestans population in the Republic of Ireland

Griffin, Denis; O'Sullivan, E.; Harmey, Matthew A.; Dowley, L. J.

doi:10.1007/bf02732216

Cited by 15 publications

(31 citation statements)

References 27 publications

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“…This multilocus genotype was also identified in three of the eight isolates from Brittany. The JE-2 isolate had mtDNA haplotype IIa, and this fingerprint was strongly associated with mtDNA haplotype IIa in several other studies (Cooke et al 2003Griffin et al 2002). Thus, the two multilocus genotypes JE-1 and JE-2 found in Jersey in the present study appear to represent common European A1 clonal lineages of P. infestans.…”

Section: Discussionmentioning

confidence: 56%

“…Zwankhuizen et al (2000) also reported this RG57 fingerprint as their A1 genotype NL-41, which was the commonest in the Netherlands between 1993 and 1996, although representing only 18% of the highly diverse population, but did not report this RG57 fingerprint among P. infestans isolates collected from potato and tomato in France in 1996 nor was it found among the eight isolates from Brittany characterised in the present study. The second multilocus genotype, JE-2, which was represented by a single P. infestans isolate from potato, has the same fingerprint as RF006 from England, Scotland, and Wales (Day et al 2004); IE-1 from Ireland (Griffin et al 2002); NI-1 from Northern Ireland ; N-1 from Norway; and F-2 from Finland (Brurberg et al 1999) and has been assigned the SSR profile 8_A1 (DEL Cooke, personal communication). This multilocus genotype was also identified in three of the eight isolates from Brittany.…”

Section: Discussionmentioning

confidence: 99%

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Characterization of Phytophthora infestans Isolates from Jersey, Channel Islands

et al. 2009

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Potato production on the island of Jersey, in the English Channel, is dominated by Jersey Royal, a selection of the early cultivar International Kidney. Jersey Royal is very susceptible to Phytophthora infestans, the cause of potato late blight, and Jersey's climate is frequently conducive to infection. During 2004-2006, isolates of P. infestans were obtained from Jersey Royal plant samples from 41 different sites (24 crops, one infected tuber, 16 volunteers) and from five outdoor tomato crops and characterised by mating type, mtDNA haplotype, Gpi and Pep allozyme genotype, metalaxyl resistance and RG57 fingerprint. A subset of 17 isolates was additionally characterised by simple sequence repeat (SSR). All but one isolate from potato belonged to a single A1 multilocus genotype or a variant. The five isolates from tomato represented three distinct genotypes, none of which was found on potato and included one which was A2 mating type. The populations of P. infestans on potato and tomato in Jersey appear distinct, with that on potato being highly clonal.

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Section: Discussionmentioning

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Characterization of Phytophthora infestans Isolates from Jersey, Channel Islands

et al. 2009

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“…On a regional basis, however, a higher proportion of UK commercial sites with A2 mating type was found in the present study in eastern and northern England and in Scotland than in other regions. There is some evidence that the frequency of A2 in Ireland has declined from a maximum of 10% of isolates in the early 1990s (O'Sullivan et al ., 1995); A2 has not been detected there in recent years (Carlisle et al ., 2001; Griffin et al ., 2002). At most sites where A2 occurred in Great Britain, A1 isolates were also found and self‐fertile isolates were not uncommon.…”

Section: Discussionmentioning

confidence: 99%

“…A similar phenomenon was reported in Scotland in 1995–97, where it was interpreted to indicate an increase in mating between resistant and sensitive strains to generate intermediate offspring (Cooke et al ., 2003a). A lower frequency of resistance was detected in Ireland in 1995 and 1996: 14% of isolates were resistant and none were intermediate in Northern Ireland (Carlisle et al ., 2001); 19% were resistant and 2% intermediate in the Republic of Ireland (Griffin et al ., 2002).…”

Section: Discussionmentioning

confidence: 99%

Phenotypic and genotypic diversity in Phytophthora infestans on potato in Great Britain, 1995–98

et al. 2004

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A total of 2691 single-lesion isolates of Phytophthora infestans was established from samples of late-blight disease from 354 commercial and garden /allotment sites in Scotland, England and Wales over four growing seasons, 1995-98. The A2 mating type was rare (3·0% of isolates) and was detected at only 34 sites. In vitro tests of sensitivity to the phenylamide fungicide metalaxyl showed that 316 sites yielded isolates with some insensitivity (resistant and/or intermediate); these were more often commercial sites than garden /allotment sites. Over the four seasons, the frequency of isolates with intermediate fungicide sensitivity increased, while the frequency of resistant phenotypes decreased. Resistant isolates were always of A1 mating type. A subset of 1459 isolates from 326 sites was analysed for molecular diversity. Mitochondrial DNA (mtDNA) haplotype Ia predominated (91·0% of isolates); haplotype IIa was present at 54 sites and both haplotypes at 33 sites. The multilocus RFLP probe RG57 detected 30 fingerprints. Four fingerprints were particularly common (RF002, RF006, RF039 and RF040) and 10 were unique to a single site in a single year. The three commonest fingerprints (RF039 > RF002 > RF006) were of A1 mating type and the fourth (RF040) was A2. RF002 isolates were resistant to the phenylamide metalaxyl and were more common in Scotland than in England and Wales. Small sample sizes limited the usefulness of estimates of diversity. Although approximately half of all sites appeared to be colonized by RF039 genotypes, some sites (both commercial and garden /allotment) showed a higher diversity, having both common and unique genotypes. The genotypic diversity within isolates collected from commercial sites and those from garden /allotment sites were similar. The contributions of sexual reproduction and alternatives to sex to the generation of variation are discussed.

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“…Molecular analysis of UK and Irish populations in the 1990s identified several common genotypes which were detected at many sites (Carlisle et al 2001;Cooke et al 2003Day et al 2004;Griffin et al 2002;Purvis et al 2001;Shaw and Wattier 2002). These were thought to be separate clonal lineages, widely but not evenly distributed over the region.…”

Section: Ukmentioning

confidence: 99%

Epidemiology and Integrated Control of Potato Late Blight in Europe

et al. 2011

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Phytophthora infestans, the causal agent of late blight, is a major threat to potato production in northwestern Europe. Before 1980, the worldwide population of P. infestans outside Mexico appeared to be asexual and to consist of a single clonal lineage of A1 mating type characterized by a single genotype. It is widely believed that new strains migrated into Europe in 1976 and that this led to subsequent population changes including the introduction of the A2 mating type. The population characteristics of recently collected isolates in NW Europe show a diverse population including both mating types, sexual reproduction and oospores, although differences are observed between regions. Although it is difficult to find direct evidence that new strains are more aggressive, there are several indications from experiments and field epidemics that the aggressiveness of P. infestans has increased in the past 20 years. The relative importance of the different primary inoculum sources and specific measures for reducing their role, such as covering dumps with plastic and preventing seed tubers from becoming infected, is described for the different regions. In NW Europe, varieties with greater resistance tend not to be grown on a large scale. From the grower's perspective, the savings in fungicide input that can be achieved with these varieties are not compensated by the higher (perceived) risk of blight. Fungicides play a crucial role in the integrated control of late blight. The spray strategies in NW Europe and a table of the specific attributes of the most important fungicides in Europe are presented. The development and use of decision support systems (DSSs) in NW Europe are described. In The Netherlands, it is estimated that almost 40% of potato growers use recommendations based on commercially available DSS. In the Nordic countries, a new DSS concept with a fixed 7-day spray interval and a variable dose rate is being tested. In the UK, commercially available DSSs are used for c. 8% of the area. The validity of Smith Periods for the new population of P. infestans in the UK is currently being evaluated.

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DNA fingerprinting, metalaxyl resistance and mating type determination of thePhytophthora infestans population in the Republic of Ireland

Cited by 15 publications

References 27 publications

Characterization of Phytophthora infestans Isolates from Jersey, Channel Islands

Characterization of Phytophthora infestans Isolates from Jersey, Channel Islands

Phenotypic and genotypic diversity in Phytophthora infestans on potato in Great Britain, 1995–98

Epidemiology and Integrated Control of Potato Late Blight in Europe

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