title: Sequence and expression variations suggest an adaptive role for the DA1-like gene family in the evolution of soybeans.
abstract: BACKGROUND
  The DA1 gene family is plant-specific and Arabidopsis DA1 regulates seed and organ size, but the functions in soybeans are unknown. The cultivated soybean (Glycine max) is believed to be domesticated from the annual wild soybeans (Glycine soja). To evaluate whether DA1-like genes were involved in the evolution of soybeans, we compared variation at both sequence and expression levels of DA1-like genes from G. max (GmaDA1) and G. soja (GsoDA1).
  
  
  RESULTS
  Sequence identities were extremely high between the orthologous pairs between soybeans, while the paralogous copies in a soybean species showed a relatively high divergence. Moreover, the expression variation of DA1-like paralogous genes in soybean was much greater than the orthologous gene pairs between the wild and cultivated soybeans during development and challenging abiotic stresses such as salinity. We further found that overexpressing GsoDA1 genes did not affect seed size. Nevertheless, overexpressing them reduced transgenic Arabidopsis seed germination sensitivity to salt stress. Moreover, most of these genes could improve salt tolerance of the transgenic Arabidopsis plants, corroborated by a detection of expression variation of several key genes in the salt-tolerance pathways.
  
  
  CONCLUSIONS
  Our work suggested that expression diversification of DA1-like genes is functionally associated with adaptive radiation of soybeans, reinforcing that the plant-specific DA1 gene family might have contributed to the successful adaption to complex environments and radiation of the plants.
authors.affiliation: State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, 100093, Beijing, China. zhaoman09@sina.com.|University of Chinese Academy of Sciences, Yuquan Road 19, 100049, Beijing, China. zhaoman09@sina.com.|College of Biological and Environmental Engineering, Zhejiang University of Technology, 310014, Hangzhou, China. zhaoman09@sina.com.
authors.forename: Man
authors.initials: M
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, 100093, Beijing, China. yongzhe@ibcas.ac.cn.|University of Chinese Academy of Sciences, Yuquan Road 19, 100049, Beijing, China. yongzhe@ibcas.ac.cn.
authors.forename: Yongzhe
authors.initials: Y
authors.lastname: Gu
authors.affiliation: State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, 100093, Beijing, China. linglihe@ibcas.ac.cn.|University of Chinese Academy of Sciences, Yuquan Road 19, 100049, Beijing, China. linglihe@ibcas.ac.cn.
authors.forename: Lingli
authors.initials: L
authors.lastname: He
authors.affiliation: College of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China. qshchen@126.com.
authors.forename: Qingshan
authors.initials: Q
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, 100093, Beijing, China. chaoying@ibcas.ac.cn.
authors.forename: Chaoying
authors.initials: C
authors.lastname: He
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics; D001483:Base Sequence; D005075:Biological Evolution; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D018525:Germination / Q000187:drug effects; D009928:Organ Specificity / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D054712:Salinity; D055049:Salt Tolerance / Q000187:drug effects / Q000235:genetics; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000494:pharmacology; D013025:Glycine max / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D013312:Stress, Physiological / Q000235:genetics
chemical_list: D010940:Plant Proteins; D012965:Sodium Chloride