Revealing the evolutionary history of tribe Leucocoryneae (Alloideae, Amaryllidaceae) based on molecular, morphological and cytogenetic data

SASSONE, A.B.

Natal

Congreso; Monocots VI; 2018

Monocots Conference

The subfamily Allioideae (Amaryllidaceae) consists of four monophyletic tribes: Allieae, Tulbaghieae, Gillieasieae, and Leucocoryneae. The Leucocoryneae encompass 6 South American genera with ca. 100 species and includes potentially medicinal, ornamental species, and weeds, either locally or worldwide distributed. This study is focused on an exhaustive sampling of Beauverdia, Ipheion, Nothoscordum, and Tristagma. Morphological and cytogenetic characters were explored through phylogenetics, phylogenomics and phylogeographic approaches using ca. 250 specimens. The findings support that the high rate of diversification within the tribe Leucocoryneae is accompanied by a slow morphological variation and can be observed as changes in genome size. These changes are a product of chromosomal rearrangements such as Robertsonian translocations or polyploidization and might be acting as reproductive barriers, being the major triggers of speciation within the tribe. Finally, Nothoscordum + Beauverdia resulted in a monophyletic group with conflictive phylogenetic signals, suggesting reticulate evolution, probably due to hybridization events. Also, a hypothesis of divergence and diversification of Ipheion is proposed.