On the origin of Solanum nigrum: can networks help?

Abstract

Black nightshades are a group of species best known for their 'poisonous' or noxious weedy reputation. It is not so well known that species of this group serve as emerging food source in many countries worldwide especially in the African continent. Despite the fact that the section has recently been studied extensively, taxonomy is still unsettled and debated because of inter- and intraspecific hybridization, phenotypic plasticity and polyploidization. In this study we analyze the genetic relationships among diploid, tetraploid and hexaploid species of sect. Solanum, which have possibly taken part in the formation of Solanum nigrum, utilizing multi-locus (SCoT, ISSR) markers combined with chloroplast trnL-F sequence data and morphological characters. We scored 51 morphological characters united with SCoT (171), ISSR (224) and trnL-F (1042), for simultaneous analysis of 49 terminals and 1488 characters. The topology of the tree is concordant with the results of the network analysis. In the phylogenetic networks, all the accessions of the diploid species shared a split with all of the polyploid species. This reflected a high portion of shared ISSR and SCoT bands between diploids and polyploids. In addition, a strong split divided the diploid species. The history of S. nigrum might be reticulate with hybrid speciation playing an important rule. Genetically differentiated diploids in few combinations have created a series of genetically distinct polyploid populations. The insufficient isolation that permitted further recombination between ancient polyploids and diploids have resulted in high level of genotypic and phenotypic polymorphism. This high level of novel genomic variability obviously enabled species to succeed in their new environment.

Cadmium, copper and zinc toxicity effects on growth, proline content and genetic stability of Solanum nigrum L., a crop wild relative for tomato; comparative study

“…It also plays an important role as a model plant. Potato (Solanum tuberosum L.), tomato (Solanum lycopersicum L.) (Poczai and Hyvönen 2011;Edmonds and Chweya 1997), and eggplant (Solanum melongena L.) are examples of this family. Tomato is the most popular and commonly cultivated seasonal vegetable crop worldwide.…”

Molecular Markers for Genetic Diversity Studies in African Leafy Vegetables

“…Poczai and Hyvönen (2011) [48] applied ISSR markers combined with start codon targeted polymorphisms (SCoT) and chloroplast sequence data as well as morphological traits to analyse the genetic relationship among diploid, tetraploid and hexaploid Solanum species of the S. nigrum complex. They found out that all the accessions of the diploid species shared a cluster with all the polyploid species, and concluded that the polyploid species have originated in few combinations of genetically differentiated diploids.…”

Genetic Variability of Thermal Nymphaea (Nymphaeaceae) Populations Based on ISSR Markers: Implications on Relationships, Hybridization, and Conservation

“…Split networks must be viewed in a more abstract way as they give a visual representation of incompatible signals in certain parts of phylogeny (Huson and Steel 2004). They also generate high portion of false negative results and for this reason the results should be handled with substantial caution (Bell and Hyvönen 2010;Poczai and Hyvönen 2011). Contrary to split NNets, recombination networks can be interpreted directly.…”