IBAM   22618
INSTITUTO DE BIOLOGIA AGRICOLA DE MENDOZA
Unidad Ejecutora - UE
artículos
Título:
Evolution of nematode-resistant Mi-1 gene homologs in three species of Solanum.
Autor/es:
TRAVAGLIA C; REINOSO H; COHEN A; LUNA C; TOMMASINO E; CASTILLO C; BOTTINI R
Revista:
MOLECULAR GENETICS AND GENOMICS
Editorial:
SPRINGER HEIDELBERG
Referencias:
Año: 2010 vol. 285 p. 207 - 218
ISSN:
1617-4615
Resumen:
Plants have evolved several defense mechanisms, including resistance genes. Resistance to the root-knot nematode Meloidogyne incognita has been found in wild plant species. The molecular basis for this resistance has been best studied in the wild tomato Solanum peruvianum and it is based on a single dominant gene, Mi-1.2, which is found in a cluster of seven genes. This nematode attacks fiercely several crops, including potatoes. The genomic arrangement, number of copies, function and evolution of Mi-1 homologs in potatoes remain unknown. In this study, we analyzed partial genome sequences of the cultivated potato species S. tuberosum and S. phureja and identified 59 Mi-1 homologs. Mi-1 homologs in S. tuberosum seem to be arranged in clusters and located on chromosome 6 of the potato genome. Previous studies suggested that Mi-1 genes in tomato have evolved rapidly by frequent sequence exchanges among gene copies within the same cluster, losing orthologous relationships. In contrast, Mi-1 homologs from cultivated potato species (S. tuberosum and S. phureja) seem to have evolved by a birth-and-death process, in which genes evolve mostly by mutations and interallelic recombinations in addition to sequence exchanges.