PCR-based markers developed by comparison of complete chloroplast genome sequences discriminate Solanum chacoense from other Solanum species

One of wild diploid Solanum species, Solanum chacoense, is one of the excellent resources for potato breeding because it is resistant to several important pathogens, but the species is not sexually compatible with potato (S. tuberosum) causing the limitation of sexual hybridization between S. tuberosum and S. chacoense. Therefore, diverse traits regarding resistance from the species can be introgressed into potato via somatic hybridization. After cell fusion, the identification of fusion products is crucial with molecular markers. In this study, S. chacoense specific markers were developed by comparing the chloroplast genome (cpDNA) sequence of S. chacoense obtained by NGS (next-generation sequencing) technology with those of five other Solanum species. A full length of the cpDNA sequence is 155,532 bp and its structure is similar to other Solanum species. Phylogenetic analysis resulted that S. chacoense is most closely located with S. commersonii. Sequence alignment with cpDNA sequences of six other Solanum species identified two InDels and 37 SNPs specific sequences in S. chacoense. Based on these InDels and SNPs regions, four markers for distingushing S. chacoense from other Solanum species were developed. These results obtained in this research could help breeders select breeding lines and facilitate breeding using S. chacoense in potato breeding.