Molecular phylogeny of saprophytic wild edible mushroom species from Tanzania based on ITS and nLSU rDNA sequences

Abstract

Tanzania is endowed with diversified topographical features rich in indigenous forests which harbor many different saprophytic wild edible mu shrooms (SWEM). Few studies have been carried out on characterizing these mushrooms, and those have used conventional methods whereby taxa were characterized using micro - and macromorphological features which are subtle and sometime fail to delimit closely related taxa. In this study, eight SWEM taxa were characterized using two molecular markers — the Internal transcribed spacer (ITS) and the nuclear large subunit (nLSU). The studied sequences were analyzed together with an additional of 19 GenBank sequences of related taxa in the genera Lentinus , Polyporus , Panus , Macrolepiota and Auricularia with maximum likelihood and Aspergillus niger as an outgroup. The BLAST search results on the NCBI database showed that the studied SWEM have ≥ 92% identity for ITS and ≥ 97 % identity for LSU. The phylogenetic tree constructed using the ITS data set revealed two major distinct clades with bootstrap support of 77% and 90% and five sub - clades supporting the five genera. The bootstrap support wer e 94% for Lentinus, 100% for Polyporus, 98% for Panus, 98% for Macrolepiota and 90 % for Auricularia , while the nLSU data set revealed the same two major distinct clades but with higher bootstrap support of 91% and 100%. The five subclades again supporting the five genera were 100% for Lentinus , 100% for Pluteus , 100% for Panus , 99% for Macrolepiota and 100% for Auricularia . From these results, it is clear that both ITS and LSU delineated the SWEM taxa to the six genera. However, the obtained support values showed that ITS sequences have the highest possibility of successful delineating the studied SWEM to species level than LSU. Moreover, the result also showed the genus Panus forming a monopyletic clade with Lentinus and Polyporus , thus contributing toward s a better understanding of its problematic taxonomic ambiguities.