Genomic characterisation of Arachis porphyrocalyx (Valls & C.E. Simpson, 2005) (Leguminosae): multiple origin of Arachis species with x = 9.

Germán Ariel Robledo,Graciela Inés Lavia,Silvestri María Celeste,José Francisco Montenegro Valls,Alejandra Marcela Ortiz

doi:10.3897/compcytogen.v11i1.10339

Abstract

The genus Arachis Linnaeus, 1753 comprises four species with x = 9, three belong to the section Arachis: Arachis praecox (Krapov. W.C. Greg. & Valls, 1994), Arachis palustris (Krapov. W.C. Greg. & Valls, 1994) and Arachis decora (Krapov. W.C. Greg. & Valls, 1994) and only one belongs to the section Erectoides: Arachis porphyrocalyx (Valls & C.E. Simpson, 2005). Recently, the x = 9 species of section Arachis have been assigned to G genome, the latest described so far. The genomic relationship of Arachis porphyrocalyx with these species is controversial. In the present work, we carried out a karyotypic characterisation of Arachis porphyrocalyx to evaluate its genomic structure and analyse the origin of all x = 9 Arachis species. Arachis porphyrocalyx showed a karyotype formula of 14m+4st, one pair of A chromosomes, satellited chromosomes type 8, one pair of 45S rDNA sites in the SAT chromosomes, one pair of 5S rDNA sites and pericentromeric C-DAPI+ bands in all chromosomes. Karyotype structure indicates that Arachis porphyrocalyx does not share the same genome type with the other three x = 9 species and neither with the remaining Erectoides species. Taking into account the geographic distribution, morphological and cytogenetic features, the origin of species with x = 9 of the genus Arachis cannot be unique; instead, they originated at least twice in the evolutionary history of the genus.

Highlights

The genus Arachis Linnaeus, 1753 (Leguminosae) is native to South America and comprises 82 nominal species
Greg. & Valls, 1994) and only one belongs to the section Erectoides: Arachis porphyrocalyx
Three of the diploid x = 9 species belong to the section Arachis: A. praecox

Summary

Introduction

The genus Arachis Linnaeus, 1753 (Leguminosae) is native to South America and comprises 82 nominal species. These species were assembled into nine sections according to morphology, geographic distribution and cross compatibility (Krapovickas and Gregory 1994, Valls and Simpson 2005, Valls et al 2013, Santana and Valls 2015). Most of species are diploid with x = 10 (2n = 20); a few (4 species) are diploid with x = 9 (2n = 18) and the rest (5 species) are tetraploid with x =10. Three of the diploid x = 9 species belong to the section Arachis: A. praecox & Valls, 1994) and one belongs to the section Erectoides: A. porphyrocalyx (Valls & C.E. Simpson, 2005)

Methods

Results

Conclusion