CHIARINI Franco Ezequiel
Cryptic genetic diversity in Solanum elaeagnifolium (Solanaceae) from South America
CHIARINI, FRANCO E.; SCALDAFERRO, MARISEL A.; BERNARDELLO, GABRIEL; ACOSTA, M. CRISTINA
AUSTRALIAN JOURNAL OF BOTANY
Solanum elaeagnifolium is a global invasive weed that is polyploid in the South American range. Our aim wasto establish the origin and distribution of these polyploid lineages, together with their relationship with the invasion ofnew habitats. Ploidy level was determined in 26 natural populations using chromosomal counts, and two non-codingplastid regions trnL-trnF and rpl32F-trnL were sequenced. Relationships among haplotypes were examined by a medianjoiningnetwork, and groups of populations were identified by employing a spatial analysis of molecular variance.Phylogenetic relationships among haplotypes were reconstructed using Bayesian inference, and divergence times wereestimated using BEAST. We found 21 haplotypes structured into three lineages: one with diploids in North Americaand invaded areas, and two in South America that developed independent polyploidisation events. The separation oflineages took place during the Pliocene with more recent divergences in the Early Pleistocene. The existence of threelineages can be attributed to the uplift of the Andes and the emergence of the Isthmus of Panama. Diversification withineach lineage may be related to the recent cyclical glacial variation throughout the Pleistocene creating haplotypediversity and recurrent polyploidy. Thus, the South American populations of S. elaeagnifolium did not originate froma recent colonisation but are established ancient lineages.