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=Root-knot nematode resistance in wild potatoes=

==Introduction==
	The cultivated potato (''Solanum tuberosum'' L. ssp. ''tuberosum'') originated in the Andes in South America and has more than 200 wild relatives. Cultivated varieties show a wide range of agronomically relevant traits, but are susceptible to several pathogens. Wild germplasm represents a valuable source for novel resistance genes that could be exploited in breeding programs.

	Parasitic nematodes infect thousands of plant species, but the most damaging are the root-knot nematodes and cyst nematodes. In Mendoza (Argentina), 7,000-9,000 hectares are destined to potato cultivars and the most problematic soil plague is the root-knot nematodes ''Meloidogyne'' spp. These nematodes attack the roots and tubers resulting in great loss of quality and production yield. The root-knot nematode, Meloidogyne incognita, causes great losses for potato breeders worldwide including Argentina, given that the cultivated potato is particularly susceptible to this nematode. Excessive amounts of fungicides must be applied with the consequent environmental concern and increasing costs. 

	Nematode resistance genes (R genes) have been described for a variety of plant species. Resistance to ''M. incognita'' has been reported for several wild potatoes, although no information regarding the underlying molecular aspects of this resistance have been studied. Genes involved in resistance to M. incognita (Mi genes) have been identified in wild tomato (''Solanum peruvianum'') and introduced into cultivated tomato (''S. lycopersicum''), a close relative to potato. Plant R genes are generally clustered in multigene families; seven Mi-1 genes are found in a single cluster in tomato.

	The project focuses on describing the genes involved in resistance to root-knot nematodes in wild species of potatoes and studying their evolution and function. Several wild potato-like species will be assessed for the level of tolerance to nematode attack. The “candidate gene approach” will be followed for identification of nematode resistance genes. Genes homologous to the gene Mi in tomato will be analyzed and an evolutionary study of the origin and phylogenetic distribution of these genes or alleles within the genus ''Solanum'' section Petota, subsection Potatoe will be performed. Furthermore, functional experiments will be followed to evaluate the function of the candidate genes by virus-induced gene silencing in resistant plants and transforming susceptible cultivated potato with the putatively-resistance gene to assess whether it confers resistance to the root-knot nematode.

==Goals==

* Evaluate wild potato species from Argentina for resistance to the nematode ''Meloidogyne incognita''.
* Estimate the number of homologous genes to the gene Mi-1 from tomato in wild potato species.
* Identify the cytogenetic basis of the resistance to ''M. incognita'' in wild potato species.
* Study the evolution of ''Mi-1'' homologs in wild potato species.

==Funding==

* 06/M053. “Estudio sobre la resistencia al nemátodo del nudo en papas silvestres”. Secretaría de Ciencia y Técnica de la U.N. Cuyo. Resolución No. 2737/2011-R. 2011-2013. Directora: Sánchez Puerta, M.V. Co-director: Dr. R.W. Masuelli. Monto total $10.000. [[Media:ResumenM053.pdf ]]

* PICT-2008-277 “Resistance genes to root-knot nematodes in tuber-bearing Solanum species”. Directora: Sánchez Puerta, M. V. 2010-2013. Monto total de $250,000. [[Media:ResumenNematodos.pdf]] 

* 06/M022. “Análisis de genes de resistencia al nemátodo del nudo en especies de papa silvestre”. Secretaría de Ciencia y Técnica de la U.N. Cuyo. Resolución No. 1094. 2009-2011. Directora: Sánchez Puerta, M.V. Monto total $10.000.


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