Population Genetic Structure of <i>Phytophthora infestans</i> in Ecuador

Forbes, Gregory A.; Escobar, Ximena C.; Ayala, Catalina C.; Revelo, Jorge; Ordoñez, M. E.; Fry, B. A.; Doucett, Katharine; Fry, William E.

doi:10.1094/phyto.1997.87.4.375

Cited by 97 publications

(88 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One of the challenges for developing good differential mixtures for late blight management in Ecuador is the apparent high degree of specific virulence in the absence of selection (8). The cost of virulence in P. infestans may be low or negligible.…”

Section: Discussionmentioning

confidence: 99%

The Effects of Host Diversity and Other Management Components on Epidemics of Potato Late Blight in the Humid Highland Tropics

Garrett¹,

Nelson²,

Mundt³

et al. 2001

Phytopathology®

View full text Add to dashboard Cite

A field study at three highland sites near Quito, Ecuador, was conducted to determine whether host-diversity effects on potato late blight would be as important as recently found in studies conducted in temperate areas. We compared three potato mixtures and use of mixtures in combination with different planting densities and two fungicide regimes. Treatment comparisons were made by absolute and relative measures of host-diversity effects and incorporating a truncated area under the disease progress curve as a means of standardizing comparisons across sites. Potato-faba intercrops consisting of only 10% potato provided an estimate of the effects of dilution of susceptible host tissue. Host-diversity effects were very different across study sites, with a large host-diversity effect for reduced disease only at the site most distant from commercial potato production. Planting density had little influence on host-diversity effects or on late blight in single-genotype stands. Fungicide use in combination with potato mixtures enhanced a host-diversity effect for reduced late blight. Potato-faba intercrops produced only a small decrease in potato late blight. Effects of host diversity on yield were variable, with the greatest increase in yield for mixtures treated with fungicides at the site most distant from commercial potato production. The effects of host diversity on late blight severity may be less consistent in the tropical highlands than in the temperate zone, but can contribute to integrated disease management.

show abstract

Section: Discussionmentioning

confidence: 99%

The Effects of Host Diversity and Other Management Components on Epidemics of Potato Late Blight in the Humid Highland Tropics

Garrett¹,

Nelson²,

Mundt³

et al. 2001

Phytopathology®

View full text Add to dashboard Cite

show abstract

“…In all cases, an effort was made to isolate from tissue containing only one lesion. Isolation was done by trapping with potato tuber slices (Forbes et al, 1997) or with a selective medium (Oyarzun et al, 1998). Isolates were maintained for short periods on Rye A and Rye B medium (Caten and Jinks, 1968) at 18°C in the dark, and stored for longer periods on Rye A agar slants at 15°C with 12-h photoperiod.…”

Section: Pathogen Collectionmentioning

confidence: 99%

“…Three of these appear to be clonal lineages, each characterized by a particular mating type, mitochondrial DNA (mtDNA) haplotype, nuclear RFLP fingerprint and isoenzyme electrophoretic pattern. Each of the three lineages has been described in detail: EC-1 (Forbes et al, 1997), US-1 (Oyarzun et a1., 1998), and EC-3 (Adler et al, 2004). Another pathogen group was described as the EC-2 clonal lineage (Ordon˜ez et al, 2000) but we have since identified new genotypes of P. infestans similar to EC-2 but differing in mating type and mtDNA haplotype.…”

Section: Introductionmentioning

confidence: 99%

“…The hosts of P. infestans in Ecuador can be attacked by different pathogen lineages or groups, but generally only one of these pathogen groups is highly aggressive on each host species (Forbes et al, 1997;Oyarzun et al, 1998;Erselius et al, 1999). This observation holds for most pathosystems we have studied, but not all.…”

Section: Introductionmentioning

confidence: 99%

“…However, subsequent isolations and pathogenicity studies were inconsistent with original observations, and new EC-1 isolates were found that were aggressive after reinoculation. We had hypothesized that EC-1 was introduced into the Andes from Europe during the last two decades and replaced US-1 as the major pathogen lineage on potato (Forbes et al, 1997) but not on tomato . Based on recent isolations of EC-1 from S. ochranthum, lineage displacement on that host also appeared to be a plausible hypothesis.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Genetic Structure of the Population of Phytophthora infestans Attacking Solanum ochranthum in the Highlands of Ecuador

Chacón¹,

Adler²,

Jarrin³

et al. 2006

Eur J Plant Pathol

View full text Add to dashboard Cite

Thirty-nine isolates of Phytophthora infestans were collected from the wild host Solanum ochranthum in the highland tropics of Ecuador and characterized with a set of phenotypic and molecular markers (mating type, metalaxyl sensitivity, the allozyme loci Gpi, and Pep, mitochondrial DNA haplotype, RFLP, and SSR), as well as for pathogenicity on various hosts. Three groups of isolates (A, B, and C) were identified based on their multilocus genotypes and variable abilities to cause disease on different hosts. Group A had a combination of alleles for the Gpi (86/100), Pep (96/100) and mtDNA (Ia) loci, as well as an RFLP fingerprint, that have not been reported for P. infestans in Ecuador, or elsewhere. Group B shares many marker characteristics with the US-1 lineage described in Ecuador on tomato, pear melon (S. muricatum), and S. caripense, but has SSR alleles not present in typical US-1 isolates. Group C for all markers tested is identical to the EC-1 lineage described on cultivated and wild potatoes in Ecuador. All isolates from S. ochranthum were able to re-infect their host of origin in the detached leaf assay; however, we did not draw clear conclusions as to the relative aggressiveness of the three groups on this host. Isolates of group A were the most specialized and were generally non-pathogenic or weakly pathogenic on all hosts other than S. ochranthum. Groups B and C infected tuber-bearing hosts, including the cultivated potato but were generally non-pathogenic on other non-tuber bearing hosts. Solanum ochranthum was infected by isolates coming from tuber-bearing Solanum hosts (i.e., the EC-1 lineage of P. infestans) and some US-1 isolates from non-tuber bearing hosts. Thus, in nature this species might be a potential reservoir of inoculum of different pathogen populations able to infect the cultivated hosts potato, tomato and pear melon (S. muricatum). Unlike potato and tomato in Ecuador, each of which is primarily attacked by a highly specialized pathogen population, S. ochranthum appears to harbour at least three pathogen groups of different genetic make-up. The unresolved issue of potential host specificity in isolates found on S. ochranthum could complicate efforts to use this species in tomato improvement.

show abstract

Oomycete Genetics and Genomics

Lamour¹,

Kamoun²

2008

View full text Add to dashboard Cite

Population Genetic Structure of Phytophthora infestans in Ecuador

Cited by 97 publications

References 19 publications

The Effects of Host Diversity and Other Management Components on Epidemics of Potato Late Blight in the Humid Highland Tropics

The Effects of Host Diversity and Other Management Components on Epidemics of Potato Late Blight in the Humid Highland Tropics

Genetic Structure of the Population of Phytophthora infestans Attacking Solanum ochranthum in the Highlands of Ecuador

Oomycete Genetics and Genomics

Contact Info

Product

Resources

About