Skip to main content
ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #248402
Title: Genetic diversity of Phytophthora infestans in the Northern-Andean region

Author
item CARDENAS, M - Universidad De Los Andes
item GRAJALES, A - Universidad De Los Andes
item SIERRA, R - Universidad De Los Andes
item ROJAS, A - Universidad De Los Andes
item GARAVITO, M - Universidad De Los Andes
item LOZANO, G - Universidad De Los Andes
item GONZALEZ-ALMARIO, A - Universidad De Los Andes
item VARGAS, A - Universidad De Los Andes
item MARIN, M - University Of Antioquia
item FERMIN, G - Universidad De Los Andes
item LAGOS, L - Universidad De Los Andes
item Grunwald, Niklaus - Nik
item BERNAL, A - Universidad De Los Andes
item SALAZAR, C - Cambridge University
item RESTREPO, S - Universidad De Los Andes

Submitted to: BMC Evolutionary Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/9/2011
Publication Date: 2/9/2011
Citation: Cardenas, M., Grajales, A., Sierra, R., Rojas, A., Garavito, M., Lozano, G., Gonzalez-Almario, A., Vargas, A., Marin, M., Fermin, G., Lagos, L.E., Grunwald, N.J., Bernal, A., Salazar, C., Restrepo, S. 2011. Genetic diversity of Phytophthora infestans in the Northern-Andean region. BMC Evolutionary Biology. 12:23.

Interpretive Summary: Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, is responsible for tremendous crop and economic losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato and, more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana) and tree tomato (Solanum betaceum), all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly studied in Colombia and Venezuela. To understand the relationships among the P. infestans populations in the Northern part of the Andes, four nuclear and one mitochondrial DNA regions were analyzed in 92 isolates of P. infestans sampled from different hosts in Colombia, Ecuador, and Venezuela. Low genetic diversity was found in the Andean region where potato has its center of origin, revealing the presence of clonal populations of the pathogen in this region. The P. infestans population genetic analysis suggests that the North Andean region is inhabited by a genetically moderately diverse population with subdivision between the Southwestern and Eastern Andes as a result of potato seed self sufficiency given that the pathogen can move with seed potatoes.

Technical Abstract: Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, is responsible for tremendous crop and economic losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato and, more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana) and tree tomato (Solanum betaceum), all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly studied in Colombia and Venezuela. To understand the relationships among the P. infestans populations in the Northern part of the Andes, four nuclear (ITS, Ras, ß-tubulin and Avr3a) and one mitochondrial (Cox1) regions were analyzed in 92 isolates of P. infestans sampled from different hosts in Colombia, Ecuador, and Venezuela. Low genetic diversity was found in the Andean region where potato has its center of origin, revealing the presence of clonal populations of the pathogen in this region. Nonetheless, sexual reproduction generates low frequency heterozygotes as consequence of a high migration rate among populations but with a poor effective gene flow. Consistently genetic differentiation exists among isolates from different regions, a pattern that might be explained by seed trading dynamics. The P. infestans population genetic analysis presented suggests that the North Andean region is inhabited by a polymorphic population with subdivision between the Southwestern and Eastern Andes as a result of potato seed self sufficiency. Additionally, Venezuela reflects a partial historic isolation that is being reinforced by a recent self-sufficiency. In summary, the P. infestans demography is mainly shaped by genetic drift and migration although diversifying selection drive the generation of new haplotypes in adaptive genes as in the Avr3a effector gene.