Phylogeny and molecular evolution of the DMC1 gene in the polyploid genus Leymus (Triticeae: Poaceae) and its diploid relatives

Abstract

The level and pattern of nucleotide variation in duplicate genes provide important information on the evolutionary history of polyploids and divergent processes between homoeologous loci within lineages. Leymus, a group of allopolyploid species with the NsXm genomes, is a perennial genus with a diverse array of morphology, ecology, and distribution in Triticeae. To estimate the phylogeny and molecular evolution of a single-copy DMC1 gene in Leymus and its diploid relatives, DMC1 homoeologous sequences were isolated from the sampled Leymus species and were analyzed with those from 30 diploid taxa representing 18 basic genomes in Triticeae. Sequence diversity patterns and genealogical analysis suggested that: (i) different Leymus species might derive their Ns genome from different Psathyrostachys species; (ii) Pseudoroegneria has contributed to the nuclear genome of some Leymus species, which might result from recurrent hybridization or incomplete lineage sorting; (iii) the Xm genome origin of Leymus could differ among species; (iv) rapid radiation and multiple origin might account for the rich diversity, numbers of species, and wide ecological adaptation of Leymus species; and (v) the DMC1 sequence diversity of the Ns genome in Leymus species was lower than that in the Psathyrostachys diploids, while the level of DMC1 sequence diversity in Leymus was higher than that in diploid Pseudoroegneria. Our results provide new insight on the evolutionary dynamics of duplicate DMC1 genes, polyploid speciation, and the phylogeny of Leymus species.

Development and application of specific FISH probes for karyotyping Psathyrostachys huashanica chromosomes

“…Thus, there are theoretically 2-times and 4-times more chromosomes carrying Oligo-44 signals of assumed autotetraploid and autooctaploid Leymus species, respectively, than in diploid Ns-genome-containing species. In the current study, the number of chromosomes giving Oligo-44 hybridization sites was 10–13 in tetraploid Leymus species and 22 in the octaploid L. arenarius (Table 5 ), implying that Leymus species are likely not autopolyploids, which is consistent with the available DNA sequence information [ 65 , 66 ]. Because small-scale analyses may lead to incomplete conclusions, more comprehensive approaches are required for future biosystematics-based investigations of the genus Leymus .…”

Roegneria yenchiana: A new species in the Triticeae (Poaceae) from the Hengduan Mountain region

“…We carried out phylogenetic analysis for the new species and its affinitive species within the Triticeae based on three unlinked single‐copy nuclear genes ( Acc1 , plastid Acetyl‐CoA carboxylase; DMC1 , disrupted meiotic cDNA; GBSSI , Granule‐Bound Starch Synthase I) and three chloroplast regions [ trn L‐F, trn L (UAA)‐ trn F (GAA); mat K, maturase coding gene; rbc L, ribulose‐1, 5‐bisphosphate carboxylase/oxygenase]. Prior to phylogenetic analysis, The Acc1 , DMC1 , GBSSI , trn L‐F, mat K, and rbc L sequences were amplified by polymerase chain reaction (PCR) using the primers listed in Table S2 under cycling conditions reported previously (Sha et al., 2016 , 2017 ), and PCR products were cloned into the pMD18‐T vector (TaKaRa, Dalian, China) following the manufacture's instruction. At least 10 random independent clones were selected for commercial sequencing.…”

Phylogenetic Relationships and Diversity in Leymus (Poaceae, Triticeae) Based on Simple Sequence Repeats Markers

“…"All the species in Leymus are polyploid with chromosome numbers ranging including tetraploid (2n=4x=28), hexaploid (2n=6x=42), octoploid (2n=8x=56), decaploid (2n=10x=70), and dodecaploid (2n=12x=84)" [3][4][5][6][7]. "They are distributed in a wide range of ecological habitats regions which from the coastal areas of the North Sea, Central Asia,and East Asia, extending to Alaska and the western areas of North America" [3,4,6,7]. "They are found particularly large in numbers on the mountains of Central Asia and North America" [4,8].…”