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Population changes inPhytophthora infestans in Taiwan associated with the appearance of resistance to metalaxyl
- Source :
- Pest Management Science. 58:951-958
- Publication Year :
- 2002
- Publisher :
- Wiley, 2002.
-
Abstract
- In recent years, late blight, caused by Phytophthora infestans (Mont) De Bary, has increased in severity in many parts of the world, and this has been associated with migrations which have introduced new, arguably more aggressive, populations of the pathogen. In Taiwan, late blight has been endemic on outdoor tomato crops grown in the highlands since the early 1900s, but recent epidemics have been more damaging. To ascertain the present status of the Taiwanese population of P infestans, 139 isolates of the pathogen collected and maintained by the Asian Vegetable Research and Development Center (AVRDC) were characterized using mating type, metalaxyl sensitivity, allozyme genotype, mitochondrial haplotype and RFLP fingerprinting. Up to 1997, all isolates were found to belong to the old clonal lineage of P infestans (US-1 and variants), but in isolates from 1998 a new genotype appeared, and by 2000 this had apparently completely displaced the old population. This new genotype was an A1 mating type and has the dilocus allozyme genotype 100/100/111, 100/100 for the loci coding for glucose-6-phosphate isomerase and peptidase, respectively. These characters, together with RG57 fingerprinting, indicated that these isolates belonged to the US-11 clonal lineage, a minority (11%) being a previously unreported variant of US-11. Whereas metalaxyl-resistant isolates were not detected in the old population, 96% of the new genotypes proved resistant, with the remainder being intermediate in sensitivity. It may be inferred from this sudden, marked change in the characteristics of the Taiwanese P infestans that a new population of the pathogen was introduced around 1997-98 and that this may well have already been metalaxyl-resistant when it arrived, although a role for in situ selection cannot be excluded.
- Subjects :
- Phytophthora
Population Dynamics
Population
Taiwan
Biology
DNA, Mitochondrial
chemistry.chemical_compound
Drug Resistance, Fungal
Genotype
Botany
Blight
education
Metalaxyl
Genetics
education.field_of_study
Alanine
Haplotype
Fungal genetics
General Medicine
biology.organism_classification
Fungicides, Industrial
Isoenzymes
Haplotypes
chemistry
Insect Science
Phytophthora infestans
Agronomy and Crop Science
Polymorphism, Restriction Fragment Length
Subjects
Details
- ISSN :
- 15264998 and 1526498X
- Volume :
- 58
- Database :
- OpenAIRE
- Journal :
- Pest Management Science
- Accession number :
- edsair.doi.dedup.....5d69e0927c2d41e789f6f33f9125fcf3