Molecular Phylogeny of Trifolium L. Section Trifolium with Reference to Chromosome Number and Subsections Delimitation.

Faten Ellmouni,Abdelfattah Badr,Ahmed Fouad,Hanan Ahmed,Hanaa El-Shazly,Linda Watson

doi:10.3390/plants10101985

Abstract

The genus Trifolium is one of the largest genera of the legume family Fabaceae with ca. 255 species. The genus is divided into eight sections; the section Trifolium is a major section of the genus, comprising 73 species mainly distributed in the Mediterranean region. We used nuclear ribosomal DNA internal transcribed spacer (ITS) and morphological variation to reconsider the delimitation and phylogenetic relationships of species in the section Trifolium with reference to chromosomal variations. Bayesian analysis of ITS data delimited the species as three clades based on the analysis of ITS sequence and informative indels in combination with morphological variation. The phylogeny of the species by different analyses methods does not support their current delimitation in 17 subsections. The basic chromosome number x = 8 is the number for the genus Trifolium, from which x = 7, 6 and 5 were derived through successive aneuploidy events. With reference to the distribution of these numbers in the species of the section Trifolium, species in clade III and clade II are more evolved than species in clade I.

Highlights

The clover genus Trifolium L. is one of the most important genera of the family Fabaceae
T. berytheum is grouped with the two samples of T. carmeli 1, 2, and T. meironense, while T. squarrosum is clustered with T. miegeanum and T. obscurum
In clade II, T. latinum and T. ligusticum are separated as a small subclade and the other 26 species are differentiated into one large subclade of 15 species and four small subclades, one of four species (T. affine, T. arvense, T. bocconei and T. dalmaticum), one of three species (T. incarnatum, T. leucanthum, T. stellatum) and two small subclades of two species each, i.e., T. molinerii grouped with T. phleoides and T. striatum with T. wettsteinii (Figure 1)

Summary

Introduction

The clover genus Trifolium L. is one of the most important genera of the family Fabaceae It comprises approximately 255 herbaceous, perennial and annual species distributed in different geographic regions, in the Mediterranean region, East Europe, Eurasia, the highlands of eastern Africa and western North America [1,2,3]. Williams et al [10] supported the hypothesis that a diploid alpine species (T. pallescens) mated with a diploid coastal species (T. occidentale) to produce tetraploid T. repens. This has spurred interest in the evaluation of the agronomic potential of locally utilized and currently uncultivated species as a potential genetic resource for crops [11]

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