Preliminary Study on the Solanum nigrum L. (Solanaceae) Complex in the Democratic Republic of the Congo

Abstract

Black nightshade, or the Solanum nigrum complex, includes a number of species that botanists consider problematic due to their morphological resemblance and the high rate of hybridization. As part of the revision of the family Solanaceae for the Flora central Africa,we realized a molecular study of the Solanum nigrum complex in the western part of the Democratic Republic of Congo. A total of 21 samples of this complex were collected and identified using the recent revision by [11]. The DNA of each specimen was extracted and then amplified by PCR for 4 molecular markers: the two nuclear regions waxy and ITS, and the two chloroplastics markers trnL-F and trnH-psbA. Additional sequences of specimens reliably identified were obtained from GenBank. The combined molecular data set allowed for the identification of two distinct groups. The first we conclude that in the western part of D.R. Congo, two species of the Solanum nigrum complex occur, both showing high morphological variability, while the true Solanum nigrum is absent from that region. The two species are Solanum americanum Mill. and Solanum scabrum Mill. The results confirm the taxonomic decisions of [11]. The generally low resolution in the analyses did not allow to visualize a geographical signal in the variation.