The Genus Machaerium (Leguminosae) is More Closely Related to Aeschynomene Sect. Ochopodium than to Dalbergia: Inferences From Combined Sequence Data

Abstract

Phylogenetic relationships among the genera Dalbergia, Machaerium, and Aeschynomene were investigated with sequences from both the chloroplast DNA trnL intron and the nuclear ribosomal DNA ITS/5.8S region. A parsimony and Bayesian analysis of individual and combined data resolved a monophyletic Dalbergia that is sister to a clade comprising Aeschynomene sect. Ochopodium and Machaerium. Aeschynomene sect. Aeschynomene is paraphyletic with respect to genera such as Bryaspsis and Soemmeringia, which collectively are sister to the Dalbergia-Machaerium-Ochopodium clade. This study identifies the disparate lineages of the genus Aeschynomene and reveals that species with basifixed stipules (i.e., sect. Ochopodium) perhaps should be ranked as a distinct genus. Species of Ochopodium have the general lomented fruit morphology in contrast to the unique indehiscent samara fruits of Machaerium. The findings of this analysis also have some bearing at the infrageneric level. Limited sampling of Dalbergia sects. Triptolemea and Ecastaphyllum resolves them as monophyletic. In contrast, the traditional infrageneric classification of Machaerium does not show much agreement with molecular groups. Additional sampling of Aeschynomene and Machaerium species, other DNA sequences, and morphological data are needed to resolve the exact relationship of sect. Ochopodium to Machaerium, as well as validate the infrageneric classification of Machaerium.

The phylogenetic analysis of Dalbergia (Fabaceae: Papilionaceae) based on different DNA barcodes

“…A few well-resolved groups, however, are seen in this study, which are consistent with the findings in previous studies. It was found that D. tamarindifolia and D. rubiginosa were closely relative to two sister species D. pinnata and D. candenatensis (Ibeiro et al 2007;Hartvig et al 2015). The sister relationship between D. ecastaphyllum and D. monetaria (members of the tropical section Ecastaphyllum (Carvalho 1997) was also observed in this study.…”

“…Furthermore, the region of nuclear ribosomal internal transcribed spacer (ITS) and the ITS2 region were also suggested as an alternative source of barcoding for flora (Chen et al 2010a;China Plant BOL Group 2011). Single or combined barcodes allows the identification of different species for a number of genera (Ibeiro et al 2007;Gonzalez et al 2009;Chen et al 2014;Jiao et al 2014). Hassold et al (2016) demonstrated that DNA barcoding is efficient to discriminate between Malagasy and non-Malagasy Dalbergia species.…”

Ecological interpretations of the leaf anatomy of amphibious species of Aeschynomene L. (Leguminosae - Papilionoideae)

“…(Solereder, 1908), genus that shares with Aeschynomene the subclade Dalbergia. According to Lavin et al (2001), some species of Aeschynomene are intimately related to Machaerium, since the genus Aeschynomene is not monophyletic (Ribeiro et al, 2007).…”

Microsatellite in Aeschynomene falcata (Leguminosae): diversity, cross-amplification, and chromosome localization

“…The Dalbergia clade position in the Papilionoideae phylogeny is well-understood (Cardoso et al, 2012); however, its internal resolution has not been well-defined. Among its taxonomic problems is the genus Aeschynomene, which is split into 2 groups (Ribeiro et al, 2007), including Aeschynomene subgen. Ochopodium (monophyletic with Dalbergia and Machaerium) and Aeschynomene subgen.…”

“…Ochopodium should be placed in another genus. Morphological, molecular, and chromosome markers have been applied for the Dalbergia clade, but the resolution of Aeschynomene remains obscure (Klitgaard and Lavin, 2005;Ribeiro et al, 2007;Queiroz and Cardoso, 2008;Polido, 2013). Taking advantage of the chromosomespecific location and transferability of SSR, we developed new chromosome markers using the microsatellite library as a source of probes for in situ localization.…”