Phylogenetic Studies Of The Chinese Thuidiaceae

The circumscription of the Thuidiaceae, phylogenetic relationships of genera and its relative were evaluated using morphology and molecular data of rbcL and rps4 gene of the chloroplast genome. A total of 12 genera and 25 taxa were examined in this study. 3 taxa of Leskeaceae and Amblystegiaceae were downloaded from Genbank for this analysis. The phylogenetic trees obtained from Neighbour Joining (NJ) and maximum likelihood (ML) methods. The results as follows: (1) In different phylogenetic trees, Anomodon, Haplohymenium and Herpetineuron always formed a monophyletic clade, combined the result with the morphological characters such as creeping stem, the growth manner of stem leaves and peristome teeth characters and so on which supports the viewpoint to isolate subfamily Anomodontoideae from Thuidiaceae and uplift it to be an independent family Anomodontaceae. (2) The phylogenetic trees deduced from the sequences of rbcL and rps4 loci, genera of Thuidioideae and Helodioideae of broud sense Thuidiaceae also formed a monophyletic clade. There were some similarities such as peristome teeth characters and differentia, but which do not overstep the subfamily, so these don't support the uplifting of Helodioideae to be a dependent family. (3) The gametophytic characters of Abietinella have a good many similarities except absence of cilia with Thuidium which is the core genus of Thuidiaceae and also similar to Boulaya. In this study, the data of absolute distances, mean character differences and sequence divergence indicate the close affinity between Abietinella and Rauiella. Abietinella always form a clade sister to Rauiella based on high bootstrap in different phylogenetic trees.So this study supports the viewpoint to place Abietinella in Thuidioideae not Helodioideae. (4) According to the phylogenetic analysis of rbcL and rps4 sequence data, information from ITS and morphological characters, the core Thuidiaceae should include Boulaya, Pelekium,Haplocladium,Cyrto-hypnum,Thuidium,Rauiella,Abietinella,Bryonoguchia,Helodium,Actinothuidium. (5) In this study, the informative sites of rbcL and rps4 account for 6.8% and 7.4% (>5%) of total length respectively, which indicates reconstruction of Thuidiaceae phylogeny based on rbcL and rps4 sequence loci is valuable.