Saturday, February 6, 2010

Amanita Species Clarified Using ITS Region

Many weeks have been spent in the lab amplifying the DNA extracted from fungal specimens and sending off the PCR products for sequencing.  I switched to a new PCR kit, Taq-Pro Red Core Kit, manufactured by Denville Scientific, Inc.  The results have been promising, with amplifications of the ITS region using primer set ITS5 and ITS4 reaching an average of nearly 70 percent.  This is quite an increase from the average amplification of 30-60 percent for the same ITS region using stock solutions and the same primer set.  The sequence results of 60 specimens from the Hartley Wood collection have been edited using Sequencher v4.8 and a BLAST search performed.  One interesting sequence helped  clarify a pure white Amanita species originally identified by me as Amanita sp. cf. virosa.  The sequence data indicated that this specimen was A. bisporigera, with a 99 percent maximum identity match. The image to the right was taken of A. bisporigera in the field and the image below is a micrograph of the 10x10 micrometer spores.  The sequence result brought up the question of how often this deadly poisonous mushroom is misidentified in the field.  It would be interesting to sample across the numerous vouchers collected from area forays and determine how often this mistake has occurred.

1 comment:

  1. Not so much a mistake, perhaps, as misapplication of a European name? Taxonomic lumping? Lots of old European names are still applied in North America; many probably need fixing. Check out what Rod Tulloss has to say about destroying angels here, in step 11.

    Rod's keys for Amanitas can't be beat, once you learn the jargon! Keep up the good work, Aaron.