Global versus Chinese perspectives on the phylogeny of the N-fixing clade

In: Journal articles
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Authors
Li H-L ,  
Chen Z-D , Hyde KD , Li D-Z , Li J , Li R-Q , Lu A-M , Mortimer PE , Naeem R , Soltis DE , Soltis PS , Su J-X , Sun M , Wang W , Wu H , Xiang X-G , Xu J-C , Zhang J-B , Zhang S-Z , Biology Department , Hope College , Holland , MI , United States , College of Life Sciences , Shanxi Normal University , Linfen , Shanxi , China , South China Agricultural University , Guangzhou , Department of Biology , University of Florida , Gainesville , FL , Florida Museum of Natural History , Genetics Institute , Key Laboratory for Plant Diversity and Biogeography of East Asia , Kunming Institute of Botany , Chinese Academy of Sciences , Kunming , Plant Germplasm and Genomics Center
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Global versus Chinese perspectives on the phylogeny of the N-fixing clade

Abstract: 

There has been increasing interest in integrating a regional tree of life with community assembly rules in the ecological research. This raises questions regarding the impacts of taxon sampling strategies at the regional versus global scales on the topology. To address this concern, we constructed two trees for the nitrogen-fixing clade: (i) a genus-level global tree including 1023 genera; and (ii) a regional tree comprising 303 genera, with taxon sampling limited to China. We used the supermatrix approach and performed maximum likelihood analyses on combined matK, rbcL, and trnL-F plastid sequences. We found that the topology of the global and the regional tree of the N-fixing clade were generally congruent. However, whereas relationships among the four orders obtained with the global tree agreed with the accepted topology obtained in focused analyses with more genes, the regional topology obtained different relationships, albeit weakly supported. At a finer scale, the phylogenetic position of the family Myricaceae was found to be sensitive to sampling density. We expect that internal support throughout the phylogeny could be improved with denser taxon sampling. The taxon sampling approach (global vs. regional) did not have a major impact on fine-level branching patterns of the N-fixing clade. Thus, a well-resolved phylogeny with relatively dense taxon sampling strategy at the regional scale appears, in this case, to be a good representation of the overall phylogenetic pattern and could be used in ecological research. Otherwise, the regional tree should be adjusted according to the correspondingly reliable global tree.