Characterization of Nematode-Resistance in the Wild Potato Species Solanum kurtzianum”

SEGURA, D., SÁNCHEZ PUERTA, M.V., MASUELLI, R.W.

Evry, Francia

Congreso; Plant genomics and Beyond Conference; 2009

Meloidogyne incognita is one of the most damaging root-knot nematodes in potato cultivars, given that the cultivated potato (Solanum tuberosum) is particulary susceptible to this plague. Highly toxic nematicides are routinely applied in excessive quantities, with a detrimental effect on the environment and substantial increase in production costs. Wild germplasm represents a highly valuable reservoir for genetic variability, including resistance genes. Genes involved in resistance to M. incognita (Mi.1 genes) have been identified in wild tomato (Solanum peruvianum) and introduced into cultivated tomato (S. lycopersicum), a close relative to potato. No resistance gene against M. incognita has been described in potato species.We aimed to characterize resistance to M. incognita in wild tuber-bearing species that coexist with the nematode. Several genotypes of the wild potato S. kurtzianum from Argentina were evaluated resulting in three genotypes of S. Kurtzianum resistant to M. incognita infection. To identify the resistance genes, we studied the Mi-1 homologous genes in potatoes by comparative genomics. Given that the potato and tomato species are closely related, it is possible to find homologous genes to the Mi-1 gene in potatoes. Using degenerate primers we amplified, cloned and sequenced a 1.6 kb fragment from a resistant genotype of S. kurtzianum and performed expression analysis. This fragment is 87% similar to the tomato Mi.1-2 gene. Phylogenetic analyses indicate a close relationship with Mi-1 genes. Characterization of nematode-resistance genes in wild potatoes is a critical step for introducing nematode resistance genes into commercial varieties.