Population genetics and phylogenetic analysis of the vrs1 nucleotide sequence in wild and cultivated barley

Spike morphology is a key characteristic in the study of barley genetics, breeding, and domestication. Variation at the six-rowed spike 1 (vrs1) locus is sufficient to control the development and fertility of the lateral spikelet of barley. To study the genetic variation of vrs1 in wild barley (Hordeum vulgare subsp. spontaneum) and cultivated barley (Hordeum vulgare subsp. vulgare), nucleotide sequences of vrs1 were examined in 84 wild barleys (including 10 six-rowed) and 20 cultivated barleys (including 10 six-rowed) from four populations. The length of the vrs1 sequence amplified was 1536 bp. A total of 40 haplotypes were identified in the four populations. The highest nucleotide diversity, haplotype diversity, and per-site nucleotide diversity were observed in the Southwest Asian wild barley population. The nucleotide diversity, number of haplotypes, haplotype diversity, and per-site nucleotide diversity in two-rowed barley were higher than those in six-rowed barley. The phylogenetic analysis of the vrs1 sequences partially separated the six-rowed and the two-rowed barley. The six-rowed barleys were divided into four groups. Key words: vrs1, nucleotide diversity, Hordeum vulgare. L'architecture de l'epi est un caractere cle pour l'etude de la genetique, de la selection et de la domestication chez l'orge. Les alleles au locus vrs1 controlent le developpement et la fecondite des epillets lateraux chez l'orge. Pour etudier la variation genetique au locus vrs1 chez l'orge sauvage (Hordeum vulgare subsp. spontaneum) et cultive (Hordeum vulgare subsp. vulgare), les sequences nucleotidiques de vrs1 ont ete determinees chez 84 orges sauvages (incluant 10 a six rangs) et 20 orges cultivees (dont 10 a six rangs) provenant de quatre populations. La sequence vrs1 amplifiee totalisait 1536 pb. Au total, 40 haplotypes ont ete identifies au sein des quatre populations. La plus grande diversite nucleotidique, haplotypique et nucleotidique par site a ete observee au sein des orges sauvages de l'Asie du Sud-Est. La diversite nucleotidique, le nombre d'haplotypes, la diversite haplotypique et la diversite nucleotidique par site etaient tous superieurs au sein des orges a deux rangs que parmi les orges a six rangs. Une analyse phylogenetique des sequences vrs1 a permis de separer partiellement les orges a six rangs des orges a deux rangs. Les orges a six rangs etaient subdivisees en quatre groupes. [Traduit par la Redaction] Mots-cles: vrs1, diversite nucleotidique, Hordeum vulgare.
Introduction The barley spike is characterized by a triple spikelet meristem (one central and two lateral spikelets) at each rachis node (von Bothmer et al. 1985). Based on the central [...]