Genetic variation and relationships among Ulex (Fabaceae) species in southern Spain and northern Morocco assessed by chloroplast microsatellite (cpSSR) markers

Abstract

Genetic variation in 27 populations of Ulex species from southern Spain and northern Morocco (Betic-Rif arc) was assessed using 11 chloroplast microsatellite (cpSSR) markers, which revealed 47 different haplotypes. These nonrecombinant, haploid markers allow measurement of genetic variation in closely related species of Ulex where molecular phylogenetic analyses have not provided a clear view of interspecific relationships. Discriminant analysis indicates that the haplotypes are useful to differentiate among species, and analysis of molecular variance (AMOVA) shows high levels of differentiation among populations. The minimum spanning tree (MST), that represents the connections between the haplotypes, suggests that the eastern Rifean U. africanus haplotypes are more genetically related than those from southern Spain. The latter may have lost genetic diversity while colonizing new habitats, eventually differentiating into U. baeticus and U. scaber. Hybridization between these populations, followed by polyploidization, may have originated the tetraploids (U. congestus and U. borgiae) that colonized new habitats associated with acidic rocks. Separate groupings of U. scaber populations may indicate multiple origins from different stocks. Diversification in this group of Ulex species could be related to the opening of the Alboran Sea by Middle Miocene, when the populations from Morocco and Spain became isolated from each other.

Chloroplast-specific universal primers and their uses in plant studies

“…Using universal chloroplast primers referred to as AS, CD and DT (Demesure et al 1995) for PCR and then digestion of amplification products, Pilepic (2002) revealed considerable degree of interspecific polymorphism between Hypericum perforatum and H. maculatum. In 2004, interspecific differences in the genus Citrullus were resolved by Dane et al Genetic variation and relationships among Ulex (Fabaceae) species in Southern Spain and Northern Morocco were similarly assessed by cpSSR markers (Cubas et al 2005). Using three universal primer pairs, Bouhadida (2007) analyzed cpDNA diversity and revealed genetic relationships in the genus Prunus.…”

Two colonisation stages generate two different patterns of genetic diversity within native and invasive ranges of Ulex europaeus

“…One of the reasons is that gorse is an allohexaploid species (2n ¼ 6x ¼ 96 chromosomes; Misset and Gourret, 1996), which complicates studies of its nuclear diversity (Clark and Jasieniuk, 2011). Also, very low cytoplasmic diversity has been found in the Ulex genus (Cubas et al, 2005;Kader Ainouche, personal communication). However, it has been shown that the phenotypic diversity is great, both in the native range and in the invaded regions (Hill et al, 1991;Tarayre et al, 2007;Hornoy et al, 2011), and that it has a genetic basis (Atlan et al, 2010).…”

“…It is a young genus (four or five million years old) within which little cytoplasmic variation has yet been found (Cubas et al, 2005;Kader Ainouche, personal communication). The Iberian peninsula (Spain and Portugal) is regarded as the centre of diversification of the Ulex genus, because it hosts a dozen Ulex species, with various ploidy levels (Feoli-Chiapella and Cristofolini, 1981).…”

Optimization of chloroplast microsatellite PCR conditions and primer screening for endangered Rheum officinale, Rheum palmatum, and Rheum tanguticum

“…This is more difficult for many nuclear SSRs, where the high heterozygosity and long size make distinct sequences difficult to obtain (Siragusa and Carimi, 2009). Therefore, they would be useful markers to gain more insights in genetic relationship studies of closely related species and populations, phylogeographic studies within a species, and marker-assisted selection (Provan et al, 2001;Cubas et al, 2005;Chen et al, 2007;Siragusa and Carimi, 2009;Melotto-Passarin et al, 2011).…”