A review of ploidy in the genus Prosopis (Leguminosae)

Abstract

The genus Prosopis contains 44 species of trees and shrubs, the majority of which originate in the Americas. Most species are reported to be diploid, with a somatic chromosome number of 2n = 28. There are rare reports of polyploidy, although it is thought that these may represent polysomaty in root tissues. However, flow cytometry has recently indicated that P. juliflora is entirely tetraploid with a somatic chromosome number of 2n = 56. In order to clarify the situation, an extensive review of ploidy in Prosopis was undertaken, the first of its kind. The ploidy levels of 124 samples of Prosopis from 21 countries, including both the natural and introduced ranges, were analysed using flow cytometry. In addition, a comprehensive literature review was carried out, examining 305 published ploidy values and covering 32 of the 44 species of Prosopis. Flow cytometry analysis suggests that P. juliflora is the only tetraploid species, with a somatic chromosome number of 2n = 4x = 56, whilst the remainder of the species analysed are diploid with 2n = 2x = 28, including the first report for P. articulata (2n = 28). A critical review of published ploidy values shows that all species of Prosopis are reported to be entirely diploid, except P. glandulosa, P. juliflora, and P. koelziana, for which both diploid and tetraploid values have been recorded.

RAPD and microsatellite transferability studies in selected species of Prosopis (section Algarobia) with emphasis on Prosopis juliflora and P. pallida

“…The P. juliflora sample from the Galapagos Islands could possess some variation with respect to the ones from the rest of the native range, but the evidence provided seems valid enough to conclude that the two species are genetically dissimilar. The differentiation of P. pallida and P. juliflora based on ploidy and morphology (Harris et al 2003;Trenchard et al 2008) corresponds with the RAPD data obtained in the present study, although more accessions of each species from their native ranges would give a more conclusive result. The clustering pattern of the Prosopis species selected in this work does not agree with the morphological criteria proposed by Burkart (1976), since species of the same series are not clustered together.…”

“…Due to their overlapping geographic range and morphological similarities, P. juliflora and P. pallida have been grouped as a complex (Pasiecznik et al 2001). Recent works on ploidy by Harris et al (2003) and Trenchard et al (2008) showed that the two species can be distinguished on the basis of their morphology and ploidy. RAPD markers also were useful in differentiating the two species (Landeras et al 2006).…”

“…The identity of P. juliflora samples from Galapagos was initially established using leaf morphology before its ploidy confirmation by flow cytometry (Trenchard et al 2008). P. juliflora populations in the Galapagos Islands might have become naturalized through numerous introductions (Wiggins and Porter 1971).…”

Características evolutivas en Prosopis spp.: citogenética, genética e hibridaciones

“…Muchos de los datos disponibles hasta la fecha sugieren que Prosopis es esencialmente un género diploide (Burkart 1976;Pasiecznik et al 2001), pero se ha informado poliploidía (Cherubini 1954;Hunziker et al 1975;Burkart 1976). Trenchard et al (2008) analizaron mediante citometría de flujo material proveniente de América e India y hallaron especies diploides (2n = 2x = 28) y tetraploides (2n = 4x = 56). Los autores concluyen, en concordancia a lo enunciado por Harris et al (2003), que P. juliflora es la única especie tetraploide y que los ejemplares triploides (2n = 3x = 42) descubiertos son casos excepcionales resultantes de la hibridación de P. juliflora (tetraploide) con un diploide, posiblemente P. pallida o P. chilensis, que ocurren en las áreas de recolección del material analizado.…”

SSR Based Genetic Diversity Analysis in Diploid Algaroba (Prosopis spp.) Population

“…are legumes, and they form a complex due to taxonomic issues not yet solved (Burkart, 1976;Pasiecznik et al, 2001). The species presents a basic chromosome number of x = 14, but the variable ploidy level present in most of the sample studies has caused cytotypes to be recognized as tetraploid (Hunziker et al, 1975;Pasiecznik et al, 2001, Nogueira et al, 2007Trenchard et al, 2008). In this case, variation from 2n = 2x = 28 to 2n = 4x = 56 was principally in the genus Prosopis (Trenchard et al, 2008).…”