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Title: First Report of Haplotype I-b of Phytophthora infestans in central Mexico

Author
item GARAY-SERRANO, E - UMSNH, MEXICO
item FERNANDEZ-PAVIA, S - UMSNH, MEXICO
item RODRIGUEZ-ALVARADO, G - UMSNH, MEXICO
item LOZOYA-SALDANA, H - UNIV CHAPINGO, MEXICO
item ROJAS-MARTINEZ, R - IFIT, MEXICO
item Goss, Erica
item Grunwald, Niklaus - Nik

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2007
Publication Date: 7/6/2007
Citation: Garay-Serrano, E., Fernandez-Pavia, S., Rodriguez-Alvarado, G., Lozoya-Saldana, H., Rojas-Martinez, R.I., Goss, E.M., Grunwald, N.J. 2007. First report of haplotype I-b of Phytophthora infestans in central Mexico. Plant Disease. 91(7):909.

Interpretive Summary: Central Mexico is considered a center of genetic diversity for the potato late blight pathogen Phytophthora infestans. This is based based on a range of genotypic and phenotypic characteristics. One puzzling aspect of the high genetic diversity found in Mexico is that one of the four described mitochondrial haplotypes (mtDNA) has not been found in central Mexico. While mtDNA haplotypes I-a, II-a and II-b have been reported from central Mexico, haplotype I-b has not been found in central Mexico. Therefore a more extensive search for haplotypes was conducted in areas where sexual reproduction occurs. During the summer of 2003, the late blight pathogen was collected in the area of Villarreal, located in Terrenate county in Tlaxcala, Mexico (170 km NE of Mexico City). Fourteen P. infestans isolates were characterized for mitochondrial DNA haplotype. Twelve isolates were mtDNA haplotype I-a and two were I-b. This is the first report of the I-b mtDNA haplotype of P. infestans from central Mexico. This report provides further evidence that Mexico is a putative center of origin for P. infestans.

Technical Abstract: Central Mexico is considered a center of genetic diversity for P. infestans based on a range of genotypic and phenotypic characteristics. Surprisingly, while mtDNA haplotypes I-a, II-a and II-b have been reported from central Mexico, haplotype I-b has not been found in central Mexico. Therefore a more extensive search for haplotypes was conducted in areas where sexual reproduction occurs. During the summer of 2003, leaflets of cultivars Rosita and Tollocan with a single lesion of late blight were collected in the area of Villarreal, located in Terrenate county in Tlaxcala, Mexico (170 km NE of Mexico City). Fourteen P. infestans isolates were characterized for mitochondrial DNA haplotype, isozyme genotype [glucose 6-phosphate isomerase (Gpi) and peptidase (Pep)] and mating type. Isolation, mating type and isozyme genotype were characterized following reported protocols. Mitochondrial DNA haplotype was determined by amplifying and digesting the P2 and P4 regions and comparing amplicons to those of reference strains of known haplotype. Twelve isolates were mtDNA haplotype I-a and two were I-b. While the mtDNA I-b has been associated with the US-1 lineage (mating type: A1, Gpi: 86/100, Pep: 92/100), the genotypes for the Mexican isolates were A2, 86/100 Gpi, 100/100 Pep from cv. Rosita and A2, 86/100 Gpi, 92/100 Pep from cv. Tollocan. This is the first report of the I-b mtDNA haplotype of P. infestans from central Mexico. This report provides further evidence that Mexico is a putative center of origin for P. infestans.