Development of a co-dominant SCAR marker linked to a putative PRSV-P resistance locus in "wild papaya"

Abstract

Molecular genetic analysis of interspecific hybrids of V. cundinamarcensis and V. parviflora using Randomly Amplified DNA Fingerprinting (RAF) has permitted the construction of genetic maps of these species. The maps presented provided a framework for the development of marker systems for detection of valuable trait loci. Subsequently, several DNA markers linked to a PRSV-P resistance gene locus were identified and mapped in V. cundinamarcensis. One of these markers (OPK41R) resulted from a Single Nucleotide Polymorphism (SNP) in close proximity to the PRSV-P resistance gene locus. The Sequence Characterised Amplified Region (SCAR) was shown to be present in both parents, and 4 additional Vasconcellea species including V. cauliflora and V. quercifolia, but not in papaya. Sequence analysis revealed several polymorphisms, one resulting in the creation of a restriction site within the OPK4IR region, which was used to convert the SCAR into an easily detected co-dominant marker. This marker presents a simple yet useful tool that may be applied as a diagnostic test for selection of homozygous PRSV-P resistant hybrids of V. cundinamarcensis. With the development of this marker there is new potential to bridge hybridisation between Hybrids of V. cundinamarcensis and C. papaya via marker assisted selection.