Phylogeny of Marasmius: an enhancement of analyses with the use of four nuc-DNA regions

Abstract

The traditional taxonomy has allowed distinguishing Marasmius from some historically close genera such as Collybia, Marasmiellus, Micromphale, Crinipellis, Chaetocalathus, etc. However, due to many disagreements in phylogenetic concern, Marasmius sensu lato (wider con-cept of Singer in 1986) were found to be a polyphyletic group by evidences that came from molecular data, splitting out the group into several others and introducing the Marasmius sensu stricto concept. Such group, restricted to representatives which have typical characteristics of Marasmius section Globulares, Hygrometrici, Leveilleani, Marasmius e Neosessiles (accepted sections to date), is still a scenario of many changes in attempt to establish an infra generic Marasmius systematic which combine both morphology and molecular data, and to reveal a relationship nearest to the reality. Despite the several segregations occurred with regard to the genus, new segregations are forecasted and, even, the current genus concept could be modified. The growing use of deeper phylogenetic analyses has been intensified and new molecular markers, with different evolutionary rates, have been developed in the sense to provide further information to the phylogenetic studies and give better resolution to the clades/groups onto the various hierarchical levels. The aim of this research project stage is to contribute with the project "Morphology and phylogenetic relationships of Marasmius (Marasmiaceae) of Atlantic rain forest areas of São Paulo State, Brazil" (FAPESP 2011/02269-1), with the improvement of the phylogenetic analyses and addition of new markers to simple and combined gene analyses, as well as with further knowledge and analyses settings which fit better to the information implied within the sequences-generated alignment, also assembled with retrieved sequences from GenBank. All obtained sequences, as well as all the morphological and taxonomic information will be those provided by the project cited above. The research stage will be carried out in the Mycology lab, Department of Natural History, Royal Ontario Museum (Toronto, Canada), and the host and collaborator researcher Dr. Jean-Marc Moncalvo will be the supervisor of the activities. The stage will be divided into two phases: 1) Sequencing; 2) Computational practices and phylogenetic analyses. The first one, a two month's duration, will consist of extraction, PCR amplification and sequencing of ITS and nLSU genes which could not be obtained in good quality because of some limitation of the samples and also obtaining of additional the nuc-DNA regions RPB2 and EF-1± to the already used genes in the project. The second phase, three month's duration, will be allocated to computational activities with sequences editing practices, alignments and phylogenetic analyses. This last phase will provide the needed knowledge to a broader analysis (more than a hundred sequences), applying new settings and commands appropriated to data for attainment of wider results and which reflect a most real relation of the representatives of the group. (AU)