Development of Molecular Markers Closely Linked to the Potato Leafroll Virus Resistance Gene, Rlr etb , for use in Marker-Assisted Selection

Abstract

Potato leafroll virus (PLRV) is a major pathogen of potato with worldwide impact on seed and commercial production of potato. In North America, the primary potato cultivars grown by industry are not resistant to PLRV and require the application of insecticides to control the aphid vector of PLRV, so as to prevent PLRV infection of the crop. The Solanum etuberosum-derived dominant gene Rlr etb confers resistance to PLRV and has been mapped to chromosome 4. The previous closest marker to Rlr etb , C2_At1g42990, was mapped 13.6 cM from the gene in a BC 3 population. Cleaved amplified polymorphic sequence markers were developed in the region surrounding C2_At1g42990 and mapped along with Rlr etb in 102 BC 4 progeny. Sixteen markers were identified surrounding Rlr etb , with flanking markers at 2.1 and 9.3 cM. Two markers, 1367-8a and DMB32-11, both 2.1 cM from Rlr etb , are shown to be well suited for marker assisted selection. The development of additional molecular markers more closely linked to Rlr etb will greatly facilitate its use in potato breeding and its continued introgression into cultivated potato for the development of PLRV-resistant cultivars.Resumen El virus del enrollamiento de la hoja de la papa (PLRV) es un patógeno importante de la papa con impacto mundial en la producción de semilla y en la producción comercial de la papa. En Norteamérica, las principales variedades de papa que se cultivan por la industria no son resistentes al PLRV y requieren de la aplicación de insecticidas para control del áfido vector del PLRV, así como para prevenir la infección del cultivo por PLRV. El gen dominante derivado de Solanum etuberosum, Rlretb, confiere resistencia al PLRV y ha sido ubicado en el cromosoma 4. El marcador previo más cercano al Rlretb, C2_At1g42990, fue ubicado a 13.6 cM del gen en una población BC3. Se desarrollaron marcadores fragmentados amplificados de secuencias polimórficas en la región que rodea a C2_At1g42990 y se les hizo un mapa junto con Rlretb en una progenie 102 BC4. Se identificaron 16 marcadores rodeando al Rlretb, con marcadores en los lados a 2.1 y 9.3 cM. Dos marcadores, 1367-8a y DMB32-11, ambos a 2.1 cM de Rlretb, se ha demostrado que son los apropiados para la selección asistida por marcadores. El desarrollo de marcadores moleculares adicionales más cercanamente ligados a Rlretb facilitará grandemente su uso en el mejoramiento de la papa así como su incorporación a papa cultivada para el desarrollo de variedades resistentes al PLRV.

Viral Diseases in Potato

“…In contrast to PVY and PVX, a good source of resistance to PLRV has long evaded breeders, but a dominant gene Rl adg conferring high levels of resistance was identified about a decade ago in a potato accession LOP-868 and the subsequently developed SCAR marker (Mihovilovich et al 2014) has enabled rapid introgression into elite germplasm (Carneiro et al 2017). Markers have also been developed for another dominant resistance gene, Rlr etb originating from the non-tuber bearing wild species S. etuberosum (Kuhl et al 2016), but its introgression into advanced breeding populations may still take time due to linkage drag from its wild progenitor. Screening of germplasm lines for ToLCNDV-[potato] resistance in field or glass house conditions showed possible presence of resistance source (Kumar et al 2015;Maan et al 2017;Jeevalatha et al 2016b).…”

The Potato Crop

“…In contrast to PVY and PVX, a good source of resistance to PLRV has long evaded breeders, but a dominant gene Rl adg conferring high levels of resistance was identified about a decade ago in a potato accession LOP-868 and the subsequently developed SCAR marker ) has enabled rapid introgression into elite germplasm (Carneiro et al 2017). Markers have also been developed for another dominant resistance gene, Rlr etb originating from the non-tuber bearing wild species S. etuberosum (Kuhl et al 2016), but its introgression into advanced breeding populations may still take time due to linkage drag from its wild progenitor. Screening of germplasm lines for ToLCNDV-[potato] resistance in field or glass house conditions showed possible presence of resistance source Maan et al 2017;Jeevalatha et al 2016b).…”

Unveiling the frontiers of potato disease research through bibliometric analysis

“…In contrast, molecular marker-assisted breeding offers a solution by integrating molecular markers with specific traits to expedite the identification of target genes. Kuhl et al ( 2016 ) had successfully created molecular markers associated with the potato leafroll virus resistance gene Rlr (etb), enabling the rapid selection of potato leafroll virus-resistant varieties through marker-assisted selection.…”