Origin of the H genome in StH-genomic Elymus species based on the single-copy nuclear gene DMC1

Previous studies have suggested that the H haplome in Elymus could originate from different diploid Hordeum species, however, which diploid species best represent the parental species remains unanswered. The focus of this study seeks to pinpoint the origin of the H genome in Elymus. Allopolyploid Elymus species that contain the StH genome were analyzed together with diploid Hordeum species and a broad sample of diploid genera in the tribe Triticeae using DMC1 sequences. Both parsimony and maximum likelihood analyses well separated the American Hordeum species, except Hordeum brachyantherum subsp. californicum, from the H genome of polyploid Elymus species. The Elymus H-genomic sequences were formed into different groups. Our data suggested that the American Horedeum species, except H. brachyantherum subsp. californicum, are not the H-genomic donor to the Elymus species. Hordeum brevisubulatum subsp. violaceum was the progenitor species to Elymus virescens, Elymus confusus, Elymus lanceolatus, Elymus wawawaiensis, and Elymus caninus. Furthermore, North American H. brachyantherum subsp. californicum was a progenitor of the H genome to Elymus hystrix and Elymus cordilleranus. The H genomes in Elymus canadensis, Elymus sibiricus, and Elymus multisetus were highly differentiated from the H genome in Hordeum and other Elymus species. The H genome in both North American and Eurasian Elymus species was contributed by different Hordeum species.

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Genomic constitution and phylogenetic position of several New Zealand Triticeae species revealed by two single copy nuclear genes

Australian Journal of Botany ◽

10.1071/bt10195 ◽

2011 ◽

Vol 59 (1) ◽

pp. 1 ◽

Cited By ~ 3

Author(s):

Aimee G. Oliver ◽

Kara Harnish ◽

Genlou Sun

Keyword(s):

New Zealand ◽

North American ◽

Diploid Species ◽

Single Copy ◽

Nuclear Genes ◽

Phylogenetic Position ◽

Genome Constitution ◽

Elymus Species ◽

New Zealand Flora ◽

Hordeum Species

Three genera of Triticeae, Elymus, Stenostachys and Australopyrum, are described in the New Zealand flora. Cytological analyses suggested that five basic genomes (St, H, Y, P and W) donated by different diploid species in different combinations exist in the genera Elymus and Stenostachys, whereas Australopyrum species contain the W genome only. Morphological and cytogenetic data suggested that the genome constitution for both E. apricus and E. multiflorus is StYW. Chloroplast DNA and ITS data supported the genome constitution of these Elymus species, but the HW genome constitution was assigned to the Stenostachys species. In this study, sequences of two single copy nuclear genes, RPB2 and DMC1, were used to confirm or refute the genome constitutions of the two Stenostachys species and the two Elymus species from New Zealand, and to analyse their phylogenetic relationships with other Elymus species. Our RPB2 and DMC1 data confirmed that the genome constitution of hexaploid E. apricus is StWY, and tetraploid S. gracilis is HW. The presence of the StW genome in hexaploid E. multiflorus, and the W genome in tetraploid S. laevis is also confirmed. No obvious St genome differentiation between New Zealand and non-New Zealand species is observed. The H genomes in the S. gracilis and S. laevis are closely related to the H genome from North American species, indicating that the H genomes in these two New Zealand species might originate from North American Hordeum species.

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Molecular phylogeny and reticulate origins of several American polyploid Hordeum species

Botany ◽

10.1139/b11-030 ◽

2011 ◽

Vol 89 (6) ◽

pp. 405-415 ◽

Cited By ~ 6

Author(s):

Huan Wang ◽

Genlou Sun

Keyword(s):

Diploid Species ◽

Nuclear Gene ◽

Single Copy ◽

Polyploid Species ◽

Sequence Comparisons ◽

Internal Transcribed Spacer Sequences ◽

Hordeum Jubatum ◽

Terminal Element ◽

Hordeum Species ◽

Genome Donors

The phylogeny of diploid species in the genus Hordeum has been studied intensively. Although the origin of American polyploid species has been analyzed using multiple-copy internal transcribed spacer sequences, the origins of these species in Hordeum remain unclear. The objectives of our study were to elucidate the origins of American polyploid species and to explore phylogenetic relationships of these polyploids to diploid Hordeum and other diploid species in Triticeae using a single copy of a nuclear gene, disrupted meiotic cDNA1 (DMC1). DMC1 sequences from nine Hordeum polyploid species were analyzed. Sequence comparisons revealed that one copy of sequences from polyploid species Hordeum fuegianum , Hordeum jubatum , and Hordeum tetraploidum showed a 82 bp miniature inverted-repeat terminal element (MITE) (Stowaway) insertion, which was also detected in the Triticeae diploid species Australopyrum species (W genome) and Taeniatherum caput-medusae (Ta genome). Maximum parsimony and Bayesian analysis suggested that diploid Hordeum brachyantherum subsp. californicum is one ancestor of polyploids Hordeum arizonicum , H. brachyantherum subsp. brachyantherum , Hordeum depressum , and Hordeum procerum . The other ancestor of tetraploid H. depressum is probably Hordeum euclaston . Hordeum cordobense was suggested to be one of the genome donors to hexaploid H. procerum. The diploid Hordeum flexuosum and tetraploid H. tetraploidum were suggested as the parents to hexaploid species Hordeum parodii . The result is that one sequence from each of three Hordeum tetrapolyploids, including H. fuegianum, H. jubatum, and H. tetraploidum, and one from Hordeum hexaploid H. arizonicum fall outside the Hordeum clade of the DMC1 phylogenetic tree, therefore representing another example of complex evolutionary history. Our data may shed light on future phylogenetic studies in Triticeae, especially for the polyploids, by broadening the scope of investigations through sampling more genome types in Poaceae, not only from the tribe Triticeae.

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