Molecular phylogenetics of Phyllanthaceae: evidence from plastid MATK and nuclear PHYC sequences

Rosabelle Samuel,Kenneth J Wurdack,Petra Hoffmann,Charles C Davis,Michael H J Barfuss,Hashendra Kathriarachchi,Mark W Chase

doi:10.3732/ajb.92.1.132

Abstract

Plastid matK and a fragment of the low-copy nuclear gene PHYC were sequenced for 30 genera of Phyllanthaceae to evaluate tribal and generic delimitation. Resolution and bootstrap percentages obtained with matK are higher than that of PHYC, but both regions show nearly identical phylogenetic patterns. Phylogenetic relationships inferred from the independent and combined data are congruent and differ from previous, morphology-based classifications but are highly concordant with those of the plastid gene rbcL previously published. Phyllanthaceae is monophyletic and gives rise to two well-resolved clades (T and F) that could be recognized as subfamilies. DNA sequence data for Keayodendron and Zimmermanniopsis are presented for the first time. Keayodendron is misplaced in tribe Phyllantheae and belongs to the Bridelia alliance. Zimmermanniopsis is sister to Zimmermannia. Phyllanthus and Cleistanthus are paraphyletic. Savia and Phyllanthus subgenus Kirganelia are not monophyletic.

Highlights

Plastid matK and a fragment of the low-copy nuclear gene PHYC were sequenced for 30 genera of Phyllanthaceae to evaluate tribal and generic delimitation
Fieldwork was conducted in Sri Lanka in collaboration and with invaluable logistic support of the Botany Department, University of Peradeniya, and in Madagascar under collaborative agreements between the Parc Botanique et Zoologique de Tsimbazaza (PBZT), the University of Antananarivo, the Association Nationale de Gestion des Aires Protegees (ANGAP), and the Royal Botanic Gardens, Kew
Analysis of the matK gene—The aligned matK matrix consisted of 1612 bp, of which 840 positions were variable, and 602 (37%) were potentially parsimony informative

Summary

Introduction

Plastid matK and a fragment of the low-copy nuclear gene PHYC were sequenced for 30 genera of Phyllanthaceae to evaluate tribal and generic delimitation. The molecular systematics of Phyllanthaceae have been investigated as part of a larger multigene study on the systematics of Euphorbiaceae s.l. The largest sampling used plastid rbcL sequences, and over 350 Euphorbiaceae s.l. sequences including 76 (74 taxa) of Phyllanthaceae, to assess subfamilial and tribal relationships (i.e., Wurdack and Chase, 1999; Wurdack, 2002; Wurdack et al, in press). The matK gene is one of the most rapidly evolving plastid protein-coding regions (Wolfe, 1991). Recent studies have shown the usefulness of this gene for resolving intergeneric or interspecific relationships among flowering plants, e.g., Malpighiaceae (Cameron et al, 2001), Poaceae (Liang and Hilu, 1996), Cornaceae (Xiang et al, 1998), Nicotiana (Aoki and Ito, 2000; Clarkson et al, in press), Chrysosplenium (Soltis et al, 2001), Hypochaeris (Samuel et al, 2003), Orchidaceae (Goldman et al, 2001; Salazar et al, 2003) and most recently across all angiosperms (Hilu et al, 2003)

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Conclusion