Phylogeny and differentiation of the St genome in Elymus L. sensu lato (Triticeae; Poaceae) based on one nuclear DNA and two chloroplast genes

BMC Plant Biology

Research Article

Xiao-Li Wang¹  Li Zhang¹  Rui-Wu Yang¹  Chun-Bang Ding¹  Jian Zeng²  Hou-Yang Kang³  Xing Fan³  Yi Wang³  Hai-Qin Zhang³  Li-Na Sha³  Zhen-Zhen Dong⁴  Yong-Hong Zhou⁴ 

[1] College of Life Science, Sichuan Agricultural University, 625014, Yaan, Sichuan, China;College of Resources and Environment, Sichuan Agricultural University, Wenjiang 611130, Chengdu, Sichuan, China;Triticeae Research Institute, Sichuan Agricultural University, Wenjiang 611130, Chengdu, Sichuan, China;Triticeae Research Institute, Sichuan Agricultural University, Wenjiang 611130, Chengdu, Sichuan, China;Key Laboratory of Genetic Resources and Crop Improvement, Ministry of Education, Sichuan Agricultural University, Wenjiang 611130, Chengdu, Sichuan, China;

关键词: Elymus;    St genome;    nr DNA;    Chloroplast gene;    Phylogeny;    Molecular evolution;   

DOI  :  10.1186/s12870-015-0517-2

 received in 2014-12-08, accepted in 2015-04-29,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundHybridization and polyploidization can be major mechanisms for plant evolution and speciation. Thus, the process of polyploidization and evolutionary history of polyploids is of widespread interest. The species in Elymus L. sensu lato are allopolyploids that share a common St genome from Pseudoroegneria in different combinations with H, Y, P, and W genomes. But how the St genome evolved in the Elymus s. l. during the hybridization and polyploidization events remains unclear. We used nuclear and chloroplast DNA-based phylogenetic analyses to shed some light on this process.ResultsThe Maximum likelihood (ML) tree based on nuclear ribosomal internal transcribed spacer region (nrITS) data showed that the Pseudoroegneria, Hordeum and Agropyron species served as the St, H and P genome diploid ancestors, respectively, for the Elymus s. l. polyploids. The ML tree for the chloroplast genes (matK and the intergenic region of trnH-psbA) suggests that the Pseudoroegneria served as the maternal donor of the St genome for Elymus s. l. Furthermore, it suggested that Pseudoroegneria species from Central Asia and Europe were more ancient than those from North America. The molecular evolution in the St genome appeared to be non-random following the polyploidy event with a departure from the equilibrium neutral model due to a genetic bottleneck caused by recent polyploidization.ConclusionOur results suggest the ancient common maternal ancestral genome in Elymus s. l. is the St genome from Pseudoroegneria. The evolutionary differentiation of the St genome in Elymus s. l. after rise of this group may have multiple causes, including hybridization and polyploidization. They also suggest that E. tangutorum should be treated as C. dahurica var. tangutorum, and E. breviaristatus should be transferred into Campeiostachys. We hypothesized that the Elymus s. l. species origined in Central Asia and Europe, then spread to North America. Further study of intraspecific variation may help us evaluate our phylogenetic results in greater detail and with more certainty.

【 授权许可】

Unknown   
© Dong et al. 2015. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.