Overview of the phylogenetic relationships of some southern Brazilian species from section Torva and related sections of "spiny Solanum" (Solanum subgenus Leptostemonum, Solanaceae)

One of the major concerns of conservation biology is the knowledge on biodiversity. Many taxa have not yet been described and plant taxonomists are working hard to change this situation. This work presents a taxonomic overview of Solanum section Torva, from South Brazil, which still poorly understood. The section includes species known as "jurubeba" which are of considerable interest because of their pharmacological properties. Despite their higher economic value, it is difficult to identify the "jurubebas" correctly due to their taxonomic problems. A few questions on evolution concerning phylogenetic relationships in this section and other related sections of subgenus Leptostemonum were investigated to clarify the species circumscription and taxonomic issues. Eighty samples were analysed based on sequence variability of the internal transcribed spacers (ITS) of the nuclear ribosomal DNA, as well as the chloroplast intron trnL, trnL-trnF and trnS-trnG spacers. Five different matrixes were analyzed as the basis for a phylogenetic approach. The combined data from the chloroplast analyses formed well-supported trees. Solanum section Torva was proposed as a monophyletic group and it is close to S. melongena, S. jamaicense and S. sisymbriifolium.