Phylogeny of Litsea and related genera (Laureae-Lauraceae) based on analysis of rpb2 gene sequences

Abstract

The relationship between Litsea and related genera is currently unclear. Previous molecular studies on these taxa using cpDNA and nrITS were unable to produce well-resolved phylogenetic trees. In this study, we explored the potential of the rpb2 gene as a source of molecular information to better resolve the phylogenetic analysis. Although rpb2 was believed to be a single-copy gene, our cloning results showed that most species examined possessed several copies of these sequences. However, the genetic distance among copies from any one species was low, and these copies always formed monophyletic groups in our molecular trees. Our phylogenetic analyses of rpb2 data resulted in better resolved tree topologies compared to those based on cpDNA or nrITS data. Our results show that monophyly of the genus Litsea is supported only for section Litsea. As a genus, Litsea was shown to be polyphyletic. The genera Actinodaphne and Neolitsea were resolved as monophyletic groups in all analyses. They were also shown to be sisters and closer to the genus Lindera than to the genus Litsea. Our results also revealed that the genus Lindera is not a monophyletic group.

The use of DNA barcoding as a tool for the conservation biogeography of subtropical forests in China

“…This result supports lower estimates of species resolution in another tropical study on barcoding Amazonian trees: 61% of species resolution for trees using rbcL + matK (Gonzalez et al, 2009). Ficus (Xu et al, 2011)], paraphyly (Litsea (Fijridiyanto & Murakami, 2009) and Lasianthus (Xiao & Zhu, 2007)), narrow species boundaries [Michelia (Nie et al, 2008)] and morphological plasticity [Rhododendron (Tsai et al, 2012)]. Our results suggest that nuclear regions are better candidates because they have higher species resolution than trnH-psbA.…”

DNA barcoding evaluation and implications for phylogenetic relationships in Lauraceae from China

“…Within the Cryptocarya group, which is basal within Lauraceae [7, 47], Cryptocarya is sister to the non-cupulate clade of Beilschmiedia . Cryptocarya has a deeply urceolate floral hypanthium that develops into a deep cupule enclosing the drupe at maturity, except for a small terminal orifice [7, 46], but Beilschmiedia lacks these characters; a synapomorphy that separates Beilschmiedia and related genera ( Endiandra and Syndiclis ) from the rest of the Cryptocarya group.…”

“…Combining DNA sequences with existing morphological characters may facilitate species identification and classification [38, 40, 41], as well as broaden our understanding of phylogenetic signal within target lineages [42]. Previous studies have shown that it is not easy to reconstruct phylogenetic relationships in Lauraceae [7, 41, 43–46], so the affinities of species and generic relationships within many of the major lineages in the family are still poorly resolved [7, 18, 43, 44, 47, 48]. …”

Beilschmiedia turbinata: A Newly Recognized but Dying Species of Lauraceae from Tropical Asia Based on Morphological and Molecular Data

“…In addition to the big phylogeny of the Lauraceae [23]–[24], a few molecular systematic studies were conducted on Lauraceae to discuss the generic relationships, e.g. Litsea complex [25]–[27], Neolitsea [26]–[28], Neocinnamomum [29]–[30], Actinodaphne [26]–[27], [31], and Persea group [32]–[33], but the Beilschmiedia group was poorly sampled. For the Beilschmiedia group in the Tropical East Asia ( Beilschmiedia , Sinopora , Syndiclis , and Endiandra ), it is difficult to separate Endiandra and Syndiclis from Beilschmiedia .…”