Phylogeny and molecular evolution of the Acc1 gene within the StH genome species in Triticeae (Poaceae)

Abstract

To estimate the phylogeny and molecular evolution of a single-copy gene encoding plastid acetyl-CoA carboxylase (Acc1) within the StH genome species, two Acc1 homoeologous sequences were isolated from nearly all the sampled StH genome species and were analyzed with those from 35 diploid taxa representing 19 basic genomes in Triticeae. Sequence diversity patterns and genealogical analysis suggested that (1) the StH genome species from the same areas or neighboring geographic regions are closely related to each other; (2) the Acc1 gene sequences of the StH genome species from North America and Eurasia are evolutionarily distinct; (3) Dasypyrum has contributed to the nuclear genome of Elymus repens and Elymus mutabilis; (4) the StH genome polyploids have higher levels of sequence diversity in the H genome homoeolog than the St genome homoeolog; and (5) the Acc1 sequence may evolve faster in the polyploid species than in the diploids. Our result provides some insight on evolutionary dynamics of duplicate Acc1 gene, the polyploidy speciation and phylogeny of the StH genome species.

Keywords: ACCase; ATP; Acc1; Acc2; Adenosine Triphosphate; COXII; CTAB; Cetyltrimethyl ammonium bromide; DMC1; GBSSI; Molecular evolution; PCR; Phylogeny; Plastid acetyl-CoA carboxylase (Acc1); RPB2; StH genome; TBR; Tree bisection–reconnection; acetyl-CoA carboxylase; gene encoding cytochrome c oxidase subunit II; gene encoding cytosolic acetyl-CoA carboxylase; gene encoding disrupted meiotic cDNA1; gene encoding granule bound starch synthase; gene encoding plastid acetyl CoA carboxylase; gene encoding the second largest subunit of RNA polymerase II; pepC; phosphoenolpyruvate carboxylase; polymerase chain reaction; trnL (UAA)–trnF (GAA) chloroplast DNA spacer region; trnL–F.