Evolution of nematode-resistance Mi-1 gene homologs in three species of Solanum

SANCHEZ PUERTA, M.V.; MASUELLI, R.W.

MOLECULAR GENETICS AND GENOMICS

SPRINGER HEIDELBERG

Año: 2011 vol. 285 p. 207 - 218

1617-4615

Plants have evolved several defense mechanisms, including resistance genes. Resistance to the rootknot 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 peruvianumMeloidogyne incognita has been found in wild plant species. The molecular basis for this resistance has been best studied in the wild tomato Solanum peruvianumSolanum 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. tuberosumMi-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. tuberosumMi-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. tuberosumS. tuberosum and S. phureja and identified 59 Mi-1 homologs. Mi-1 homologs in S. tuberosumMi-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 have suggested that Mi-1 genes in tomato evolved rapidly by frequent sequence exchanges among gene copies within the same cluster, losing orthologous relationships. In contrast,Mi-1 genes in tomato 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-1 homologs from cultivated potato species (S. tuberosum and S. phureja) seem to have evolved by a birth-anddeath process, in which genes evolve mostly by mutations and interallelic recombinations in addition to sequence exchanges.S. phureja) seem to have evolved by a birth-anddeath process, in which genes evolve mostly by mutations and interallelic recombinations in addition to sequence exchanges.