Divide to Conquer: Evolutionary History of Allioideae Tribes (Amaryllidaceae) Is Linked to Distinct Trends of Karyotype Evolution

Abstract

Allioideae (e.g., chives, garlics, onions) comprises three mainly temperate tribes: Allieae (800 species from the northern hemisphere), Gilliesieae (80 South American species), and Tulbaghieae (26 Southern African species). We reconstructed the phylogeny of Allioideae (190 species plus 257 species from Agapanthoideae and Amaryllidoideae) based on ITS, matK, ndhF, and rbcL to investigate its historical biogeography and karyotype evolution using newly generated cytomolecular data for Chilean Gilliesieae genera Gethyum, Miersia, Solaria, and Speea. The crown group of Allioideae diversified ∼62 Mya supporting a Gondwanic origin for the subfamily and vicariance as the cause of the intercontinental disjunction of the tribes. Our results support the hypothesis of the Indian tectonic plate carrying Allieae to northern hemisphere ('out-of-India' hypothesis). The colonization of the northern hemisphere (∼30 Mya) is correlated with a higher diversification rate in Allium associated to stable x = 8, increase of polyploidy and the geographic expansion in Europe and North America. Tulbaghieae presented x = 6, but with numerical stability (2n = 12). In contrast, the tribe Gilliesieae (x = 6) varied considerably in genome size (associated with Robertsonian translocations), rDNA sites distribution and chromosome number. Our data indicate that evolutionary history of Allioideae tribes is linked to distinct trends of karyotype evolution.

Genomic, karyological and morphological changes of South American garlics (Ipheion) provide insights into mechanisms of speciation in the Pampean region

“…The tribe Leucocoryneae (Allioideae: Amaryllidaceae) includes six genera and ~150 species, all but one of these taxa occurring only in South America (Sassone et al, 2014). Within the subfamily Allioideae, the tribe originated ~37-31 million years ago and they have diversified in terms of number and geographical range of species (Costa et al, 2020). Species of the tribe Leucocoryneae exhibit a variety of ecological adaptations (occurring in high elevations in the Andes to sea level in the Pampas prairies), of morphological traits (from uniflowered species to species having bi-or multiflowered inflorescences, showing a variety of flower pigmentation), and interesting karyological variability among genera.…”

Allium pallasii and A. caricifolium—Surprisingly Diverse Old Steppe Species, Showing a Clear Geographical Barrier in the Area of Lake Zaysan

“…All subsequent phylogenetic studies [ 7 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ] confirmed the division of Allium into three major evolutionary lineages with the monophyletic origin of all subgenera included in the first and second evolutionary lineages. The phylogenetic relationships in the youngest third lineage are less clear.…”

Molecular and Cytogenetic Analysis of rDNA Evolution in Crepis Sensu Lato

“…The interpretation of the rDNA loci distribution patterns in a phylogenetic context not only enables a better understanding of their evolution but also provides an insight into the evolution of the whole karyotype structure [ 21 , 22 , 23 ]. The most common reconstructed ancestral character state was the presence of a chromosome with both rDNA loci in one arm in the Crepis karyotype.…”

“…Comparative mapping of chromosomal markers might enable at least some chromosomal rearrangements to be identified and thus enable a better understanding of the patterns of their chromosomal evolution [ 17 , 18 ]. 5S and 35S rDNAs are most often used as chromosomal markers, as they are highly repetitive, arranged in tandem arrays and highly conserved in the DNA sequence of the coding regions [ 19 , 20 , 21 , 22 , 23 ]. The non-transcribed spacer (NTS) of 5S rDNA and the internal transcribed spacer of 35SrDNA (nrITS 1 and 2) evolve much faster than their coding regions and are thus often used as molecular markers in phylogenetic analyses [ 24 ].…”