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Citation for Study 10828

About Citation title: "Molecular phylogenetics of suborder Cactineae (Caryophyllales), including insights into photosynthetic diversification and historical biogeography".
About Study name: "Molecular phylogenetics of suborder Cactineae (Caryophyllales), including insights into photosynthetic diversification and historical biogeography".
About This study is part of submission 10818 (Status: Published).

Citation

Ocampo G.A., & Columbus J. 2010. Molecular phylogenetics of suborder Cactineae (Caryophyllales), including insights into photosynthetic diversification and historical biogeography. American Journal of Botany, 97(11): 1827-1847.

Authors

  • Ocampo G.A.
  • Columbus J.

Abstract

Premise of the study: Phylogenetic relationships were investigated among the eight families (Anacampserotaceae, Basellaceae, Cactaceae, Didiereaceae, Halophytaceae, Montiaceae, Portulacaceae, Talinaceae) forming suborder Cactineae (= Portulacineae) of the Caryophyllales. In addition, photosynthesis diversification and historical biogeography were addressed. Methods: Chloroplast DNA sequences, mostly noncoding, were used to estimate the phylogeny. Divergence times were calibrated using two Hawaiian Portulaca species, due to the lack of an unequivocal fossil record for Cactineae. Photosynthesis pathways were determined from carbon isotope ratios (13C) and leaf anatomy. Key results: Maximum likelihood and Bayesian analyses were consistent with previous studies in that the suborder, almost all families, and the ACPT clade (Anacampserotaceae, Cactaceae, Portulacaceae, Talinaceae) were strongly supported as monophyletic; however, relationships among families remain uncertain. The age of Cactineae was estimated to be 18.8 million years. 13C and leaf anatomy were congruent in most cases, and inconsistencies between these pointed to photosynthetic intermediates. Reconstruction of photosynthesis diversification showed C3 to be the ancestral pathway, a shift to C4 in Portulacaceae and five independent origins of CAM. Cactineae were inferred to have originated in the New World. Conclusions: Although the C3 pathway is inferred as the ancestral state in Cactineae, some CAM activity has been reported in the literature in almost every family of the suborder, leaving open the possibility that CAM may have one origin in the group. Incongruence among loci could be due to internal short branches, which possibly represent rapid radiations in response to increasing aridity in the Miocene.

Keywords

C4; Cactineae; Cactaceae; CAM; Caryophyllales; divergence times; historical biogeography; photosynthesis diversification; Portulacaceae; Portulacineae.

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  • Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S10828
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