Comparison of Acetyl-CoA carboxylase 1 (Acc-1) gene diversity among different Triticeae genomes

It has widely been documented that life form and mating system have significant influences on genetic diversity. In the tribe Triticeae, several genera contain both annual and perennial species, whereas other genera comprise strictly annual or perennial species. It was suggested that Triticeae annuals have originated from Triticeae perennials. The present study aims to analyze nucleotide diversity of Acc-1 gene among different Triticeae genomes, and attempts to link effects of life history (annuals and perennials) and mating systems. The nucleotide diversity of 364 Acc-1 sequences in Triticeae species was characterized. The highest estimates of nucleotide diversity values (π = 0.01919, θ = 0.03515) were found for the Ns genome among the genomes analyzed. Nucleotide diversities in the D genome and Ns genome of polyploids are higher than those in respective genomes of diploids, while in the St genome of polyploids, it is lower than that in the St genome of diploids. The averaged π value (0.013705) in the genomes of perennials is more than twice of the value (0.00508) in the genomes of annuals. The averaged π value (0.01323) in the genomes of outcrossing species is two-fold of the value (0.005664) in the genomes of selfer. Our results suggested that the evolutionary history and mating system may play an important role in determining nucleotide diversity of Acc-1 gene in each genome.