Evolution Of Sequestrate Cortinarius In New Zealand

Abstract

In order to investigate the evolution of sequestrate fungi in New Zealand, phylogenetic analyses were carried out to discover the relationships between sequestrate fungi and their relatives. Three loci (ITS, LSU and RPB2) were chosen for creating multi-gene phylogenies with 142 Cortinarius taxa. The results of the present study indicated that sequestrate Cortinarius species from New Zealand have evolved multiple times and their relatives include species from New Zealand and other countries such as Australia. All the phylogenies using different loci show very similar results in terms of topology. The results of phylogenetic analyses indicated that at least in Cortinarius, the ITS region is powerful and accurate for determining lower level relationships between species exclusively. Several issues were also detected in the present study: i) multi-loci phylogeny did not significantly improve resolutions at the higher level, therefore it is very hard to determine the relationships between distantly related Cortinarius species; ii) The existence of sequences obtained from misidentified and/or mislabeled collections in the public accessible NCBI database could mislead other researchers and cause consequential problems; iii) Many Cortinarius species were named and published by morphological characters and without molecular data. However, morphological features are sometimes misleading. The present study has denoted several species with almost identical ITS sequences but which were identified as different species. The present study also contributed to the whole genome sequencing study of Cortinarius beeverorum and Cortinarius dulciolens by extracting both DNA and RNA for sequencing. C. dulciolens and, C. beeverorum, two closely related species with exceptional morphological differences (mushroom form vs. sequestrate form) were chosen for sequencing their whole genomes and trancriptomes in order to investigate the genetic changes through transformation from mushroom form to sequestrate form.