| Abstract Detail
Thursday Morning Contributed Talks Oliva, Ricardo [1], Chacon, Gabriela [1], Cooke, David [2], Lees, Alison [2], Forbes, Gregory [3]. Is Phytophthora infestans a good taxonomist - host recognition in the Phytophthora/Solanum interaction? THE greatest genetic diversity in the population of Phytophthora infestans attacking potato has been found in Mexico, the purported center of origin of the pathogen. However, more diverse pathogen genotypes have been found in the Andes, particularly Ecuador, if one considers the populations attacking other Solanum hosts, such as pear melon (Solanum muricatum), tomato tree (S. betaceum) and naranjilla (S. quitoense). Host specificity in the Andean population of P. infestans has been detected, but it is often quantitative (one pathogen population is more aggressive than others) and difficult to demonstrate in greenhouse inoculations. Overall, there is confusion on the subject of host specificity and researchers have not been able to construct general hypotheses that fit all the data. The confusion may arise from real variability in the systems (some populations may equally aggressive on several hosts, while others are highly specific), but it may also arise from poor resolution of pathogen subpopulations and even some host populations (e.g., the group Anarrhichomenum). To study host specificity in this system, and to orient future inoculation trials, we have evaluated a large sample of the P. infestans collection in Ecuador with microsatellites (SSR). This paper presents the analyses of SSR data indicating general grouping of subpopulations from particular hosts. One large group of isolates from the sections Jugandifolia and Lasiocarpa, the group Anarrhichomenum and the wild tree S. hispidum is genetically distant from the potato P. infestans and probably constitutes a new species, P. andina. Within P. infestans, there are subpopulations attacking potato, tomato and pear melon. Pathogen diversity within P. andina may represent host specific sub-groups, but testing this hypothesis will probably require further sampling and phenotypic evaluations of aggressiveness.
Log in to add this item to your schedule
1 - International Potato Center (CIP), Plant Pathology, Panamericana Sur Km 1, P.O. Box 17-21-1977, Quito, Pichincha, 0000, Ecuador
2 - Scottish Crop Research Institute (SCRI), Programme of Host-Parasite Co-Evolution, DD2 5DA, Dundee, , UK
3 - International Potato Center (CIP), Plant Pathology, Apartado 1558, Lima 12, , Peru
Keywords:
Phytophthora infestans
Microsatellites
Solanum
host recognition.
Session: SOL06-2
Location: Ballroom AB/Monona Terrace
Date: Thursday, July 27th, 2006
Time: 8:30 AM
Abstract ID:241 |
