Molecular Phylogeny of Chinese Thuidiaceae with emphasis on Thuidium and Pelekium

TL;DR

This study uses molecular data from chloroplast and nuclear DNA sequences to clarify the phylogenetic relationships within Thuidiaceae, supporting the monophyly of Thuidium and Pelekium and revising family classifications.

Contribution

It provides a comprehensive molecular phylogeny of Thuidiaceae, emphasizing the importance of ITS and chloroplast sequences in resolving genus-level relationships.

Findings

Thuidium and Pelekium are monophyletic groups.

Thuidiaceae includes some Leskeaceae genera.

ITS sequences are crucial for phylogenetic resolution.

Abstract

We present molecular phylogenetic investigation of Thuidiaceae, especially on Thudium and Pelekium. Three chloroplast sequences (trnL-F, rps4, and atpB-rbcL) and one nuclear sequence (ITS) were analyzed. Data partitions were analyzed separately and in combination by employing MP (maximum parsimony) and Bayesian methods. The influence of data conflict in combined analyses was further explored by two methods: the incongruence length difference (ILD) test and the partition addition bootstrap alteration approach (PABA). Based on the results, ITS 1& 2 had crucial effect in phylogenetic reconstruction in this study, and more chloroplast sequences should be combinated into the analyses since their stability for reconstructing within genus of pleurocarpous mosses. We supported that Helodiaceae including Actinothuidium, Bryochenea, and Helodium still attributed to Thuidiaceae, and the monophyletic Thuidiaceae s. lat. should also include several genera (or species) from Leskeaceae such as Haplocladium and Leskea. In the Thuidiaceae, Thuidium and Pelekium were resolved as two monophyletic groups separately. The results from molecular phylogeny were supported by the crucial morphological characters in Thuidiaceae s. lat., Thuidium and Pelekium.