Molecular characterisation of Solanum melongena L. and the crop wild relatives, S. violaceum Ortega and S. torvum Sw., using phylogenetic/DNA barcoding markers

Abstract

The Leptostemonum clade (Solanum subgenus Leptostemonum Bitter) species Solanum melongena L. (the aubergine) is an economically important crop which requires the acquisition of adaptive traits, potentially from its wild relatives of the same clade, to reduce its susceptibility to biotic and abiotic stress. The application of matK, rbcL, psbA-trnH and ITS2 to Leptostemonum clade phylogeny and DNA barcoding is not documented. In this study, PCR amplification and direct sequencing of these markers from S. melongena, S. violaceum Ortega and S. torvum Sw., with commonly used primers, were tested. The four DNA regions were amplified from these species. matK, rbcL and psbA-trnH were successfully sequenced. Unlike rbcL, matK and psbA-trnH could singly produce species-specific groups in phylogenetic analyses, which showed species relationships consistent with those from previously published phylogenies determined using other chloroplast and nuclear DNA regions. The phylogeny from matK+psbA-trnH exhibited high bootstrap support for the S. melongena group as well as intraspecific resolution within S. violaceum. In the context of testing the use of DNA barcoding to discriminate between S. violaceum and S. anguivi Lam., interspecific and intraspecific p-distances for matK, rbcL and psbA-trnH in these two species were compared. No barcode gap or diagnostic character was found, thus eliminating these three markers as potential DNA barcodes to discriminate between S. violaceum and S. anguivi.