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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETIC ENHANCEMENT AND MANAGEMENT OF WARM SEASON GRASS SPECIES FOR FORAGE AND ALTERNATIVE USES

Location: Crop Genetics and Breeding Research

Title: Phylogenetic analysis reveals multiple introductions of Cynodon species in Australia

Authors
item Jewell, M -
item Frere, C -
item Harris-Shultz, Karen
item Anderson, William
item Godwin, I -
item Lambrides, C -

Submitted to: Molecular Phylogenetics and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 29, 2012
Publication Date: November 1, 2012
Citation: Jewell, M., Frere, C.H., Harris-Shultz, K.R., Anderson, W.F., Godwin, I.D., Lambrides, C.J. 2012. Phylogenetic analysis reveals multiple introductions of Cynodon species in Australia. Molecular Phylogenetics and Evolution. 65(2):390-396.

Interpretive Summary: Up until now, no genetic analysis had been made on the origin, diversity and phylogenetic history of bermudagrass (Cynodon sp) within Australia. A study was performed to determine maternal genetic relatedness of bermudagrass accessions collected within Australia with accessions derived from an international collection. This was performed by sequencing chloroplast DNA. There was no evidence of any native Cynodon species in our dataset, but instead were able to genetically confirm that at least six Cynodon species (C. transvaalensis, C. incompletus, C. hirsutus, C. radiatus, C. plectostachyus and C. dactylon) are present in Australia. While C. plectostachyus had not been recorded to exist in Australia, our analysis suggested its presence. The data strongly indicated that Cynodon species were introduced into Australia from multiple recent introduction events, which most likely occurred in the last 500 years and that there are were previously identified C. dactylon genotypes that were divergent indicating a possible undescribed species of Cynodon.

Technical Abstract: The distinction between native and introduced flora in Australia presents some unique challenges given its geological and colonization history. While it is believed that seven species of Cynodon are present in Australia, no genetic analyses, to date, have investigated the origin, diversity and phylogenetic history of Cynodon within Australia. To address this gap, 147 samples (92 from across Australia and 55 representing global distribution) were sequenced for a total of 3336 bp of chloroplast DNA spanning six genes. Overall, we found no evidence of any native Cynodon species in our dataset, but instead were able to genetically confirm that at least six Cynodon species (C. transvaalensis, C. incompletus, C. hirsutus, C. radiatus, C. plectostachyus and C. dactylon) are present in Australia. While C. plectostachyus had not been recorded to exist in Australia, our analysis suggested its presence. Patterns of haplotype diversity strongly indicated that Cynodon species were introduced into Australia from multiple recent introduction events, which most likely occurred in the last 500 years. More importantly, two haplotypes commonly present in Australia and internationally, formed a monophyletic clade which showed levels of species divergence from previously identified Cynodon species. Our study suggests that these two haplotypes, which previously grouped with C. dactylon, may represent an undescribed species of Cynodon.

Last Modified: 4/20/2014
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