Resistance to Ralstonia solanacearum of Sexual Hybrids Between Solanum commersonii and S. tuberosum

Abstract

This research was carried out to study the levels of bacterial wilt resistance and genetic diversity of (near) pentaploid sexual hybrids between S. commersonii (2n=2x= 24, 1EBN) and cultivated S. tuberosum. Following artificial inoculations with Ralstonia solanacearum, wilting degree was estimated on a scale from 0 to 4, and seven genotypes of 26 (27%) displaying a S. commersonii like behavior were identified. Latent bacterial colonizations were detected in roots of symptomless S. commersonii and hybrids, whereas no bacterial populations were detected within stems. This suggests that the movement and/or growth of the bacterium in the aerial part were strongly inhibited. A molecular study with AFLP markers clustered hybrids into nine groups and provided evidence that resistant hybrids were slightly more similar to cultivated S. tuberosum than to the wild parent. This is important in view of the re-establishment of the cultivated genetic background through backcrosses. Hybrids displayed good fertility and are being used for further breeding efforts.Resumen Esta investigación fue realizada para estudiar los niveles de resistencia a la marchitez bacteriana y la diversidad genética de híbridos sexuales (casi) pentaploides entre S. commersoni y S. tuberosum cultivado. Después de las inoculaciones artificiales con Ralstonia solanacearum, la marchitez fue estimada en una escala de 0 a 4 y se identificaron siete genotipos de 26 (27%) que se comportaron como S. commersoni. Se detectaron colonizaciones bacterianas latentes en raíces que no presentaban síntomas de S. commersoni e híbridos mientras que no se detectó población bacteriana dentro de los tallos. Esto sugiere que el movimiento y/o crecimiento de la bacteria en la parte aérea fue fuertemente inhibido. Un estudio molecular con marcadores AFLP agrupó los híbridos en nueve grupos y dio la evidencia de que los híbridos fueron ligeramente más similares al S. tuberosum cultivado que sus progenitores silvestres. Esto es importante en vista del restablecimiento de los antecedentes genéticos de la especie cultivada por medio de retro cruzamientos. Los híbridos mostraron buena fertilidad y están siendo usados para mejoramiento.

The Solanum commersonii Genome Sequence Provides Insights into Adaptation to Stress Conditions and Genome Evolution of Wild Potato Relatives

“…It derived from a single seed from accession PI243503 obtained from the Inter-Regional Potato Introduction Station, Sturgeon Bay, Wisconsin (Supplemental Figure 2). This clone has been widely characterized and used in our breeding program as a source of resistance genes to biotic and abiotic stresses (Carputo et al, 1997(Carputo et al, , 2007(Carputo et al, , 2009(Carputo et al, , 2013.…”

Management of Bacterial Wilt [Rhalstonia solanacearum Yabuuchi et al., 1995] of Potatoes: Opportunity for Host Resistance in Kenya

“…However, this resistance is overcome by high temperature (French & Lindo, 1982;French, 1994;French et al, 1998). Other sources of resistance which have been evaluated, albeit at experimental level, are S. stenotomum L (cultivated), and S. commersonii Dun, which is wild (Laferriere et al, 1999;Fock et al, 2000;Carputo et al, 2009). They too show moderate resistance and their hybrids harbour latent infection (Laferriere et al, 1999;Fock et al, 2000;.…”

A Novel, Sensitive Method to Evaluate Potato Germplasm for Bacterial Wilt Resistance Using a LuminescentRalstonia solanacearumReporter Strain

“…In potato, breeding programs for resistance to bacterial wilt have used wild species related to Solanum tuberosum as sources of resistance (Narancio et al 2013;Sequeira and Rowe 1969). Initially, S. phureja was used to successfully introgress resistance (Carputo et al 2009;French and De Lindo 1982;Sequeira and Rowe 1969). More recently, the tuber-bearing species S. commersonii Dun (Hawkes 1994) has emerged as a source of high resistance against bacterial wilt.…”

“…More recently, the tuber-bearing species S. commersonii Dun (Hawkes 1994) has emerged as a source of high resistance against bacterial wilt. This wild species exhibits a high genetic diversity (Pianzzola et al 2005;Siri et al 2009) and encodes many desirable traits, such as tolerance to low temperatures and resistance to several pathogens, including R. solanacearum (Carputo et al 2009;Galván et al 2006;Gonzalez et al 2013;Kim-Lee et al 2005;Laferriere et al 1999;Narancio et al 2013;Siri et al 2009). Due to these valuable traits, S. commersonii is being used as the main genetic resource for the potato breeding program held in Uruguay, focused on the development of improved potato varieties with high levels of field resistance to bacterial wilt (Galván et al 2006;Gonzalez et al 2013;Narancio et al 2013).…”