Molecular Phylogeny Of Rhytismatales From Conifers

Members of the Rhytismatales have a comprehensive biological diversity and a broad host spectrum.Their hosts belong to nearly 58 families,including gymnosperms, angiosperms and ferns.The Rhytismatales are a great important component of the world fungi resources.The history for classification of Rhytismatales is long and complex,but knowledge of molecular phylogeny of this group and the related fungi are limited.In this study,62 28S-rDNA sequences and 17 ITS sequences were gained,three kinds of sequences,28S-rDNA,ITS and their joint sequences were used for analyses of Maximum Parsimony(MP) methods and Neighbor-Joining(NJ) methods by PAUP*4.0b10 software.The posterior probabilities of Bayesian Inference and the bootstrap of Jackknife were used to evaluate the trees.The results were as followed:(1) Traditional members of Rhytismatales,Naemacyclus sp.526c and Cyclaneusma minus 45 were more closely related to Helotiales.According to the morphological studies,members belong to Cudoniaceae,Helotiales,however,Cudonia lutea,cudonia circinans,Cudonia sichuanensis,Spathularia flavida occured on the Rhytismatales clade.This is similar to the analysis of the 28S-rDNA analysis by Hou (2004) and the analysis of 18S-rDNAby Gernandt et al.(2001).(2) Rhytismatales from conifers formed a large clade,and those from broadleaf-hosts gathered together,but still in the conifer clade,The members of Rhytismatales from different host ogans of conifers formed own clade.(3) Molecular Phylgentic analyses results were not congruous with those of traditional classification.The species Meloderma desmazieri AF203470,Meloderma desmazieri AF426056,Elytroderma deformans AF203469 occurred in the Lophodermium clade in ITS trees.Theresore some morphological characters,such as the shape of ascocarps,ascus and ascospores and the position of ascocarps in the host,as were not important at the generic level.(4) The phylogenetic trees based on sequences of ITS,LSU and ITS+LSU rDNA were similar.Some clades have a high boostrap and posterior probability support, while the others with only lower supports.Therefore multigene analysis is proposed,for example,to combine the sequences of ITS,LSU,SSU,RPB2 or mtSSU to make a further study.