Observation 289175: Russula

Notes:
Pale (white or cream) spore print

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Proposed Names

28% (1)
Recognized by sight: Russula or Lactarius – need to know if the mushroom exudes a latex
47% (2)
Based on chemical features: ITS rDNA
85% (1)
Recognized by sight

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= Observer’s choice
= Current consensus

Comments

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Re the ITS sequence
By: I. G. Safonov (IGSafonov)
2019-10-28 18:51:44 PDT (-0700)

Your sequence is a partial one, Alden. I always annotate my sequences by finding primers and regions within sequences by searching for the beginning and ending motifs. In the case of ITS, its ITS1, 5.8S and ITS2. When I couldn’t find these, it dawned on me that your sequence needs to be reversed and complemented first.
Cutting to the chase, your sequence consists of the last 94 characters of ITS1, the entire 5.8S region (160 bps) and what I believe is the complete ITS2 region of 260 bps.
The last 8 characters of your sequence (CTGACCTC) appear to be the scrambled start of the LSU region in Russula (TTGACCTCAAATCG).
The ITS2 region of your mushroom is only 4 characters different from that of R. delica KX812842, of which 2 are not significant because they are the extra "A"’s in the short homopolymeric motif.
I don’t know if KX812842 was identified correctly because there are 15 more records of R. delica in GenBank. I BLASTn-ed the full-length ITS sequence of KX812842, and the similarity to the other hits was 84-99%, with the query cover of 78-100% (with exception of one 50% cover).

Hi Eva,
By: Alden Dirks (aldendirks)
2019-10-28 17:39:02 PDT (-0700)

Do you have a citation with that information? Bazzicalupo et al. (2017) report R. delica as occurring in Washington. I’m curious to know more about the distributions of these various Russula species.

Bazzicalupo, A. L., Buyck, B., Saar, I., Vauras, J., Carmean, D., & Berbee, M. L. (2017). Troubles with mycorrhizal mushroom identification where morphological differentiation lags behind barcode sequence divergence. Taxon, 66(4), 791–810. https://doi.org/10.12705/664.1

Russula brevipes
By: Eva Skific (Evica)
2019-10-28 17:13:02 PDT (-0700)

is American (delica)
and var. ocior has blue line between stem and gills

In the first photo,
By: Alden Dirks (aldendirks)
2019-10-28 16:56:47 PDT (-0700)

if I use my imagination, I do think I can see some bluish coloration at the top of the stem by the gills, which would indicate this is R. chloroides. I’ll have to check the dried specimen to see if any color is evident

ITS sequence added
By: Alden Dirks (aldendirks)
2019-10-28 16:55:10 PDT (-0700)
Could be R. delica or R. chloroides. or maybe something else
By: Alden Dirks (aldendirks)
2019-10-28 16:54:10 PDT (-0700)

Top hit is 99% query coverage, 98.64% identical, accession KX812842, which is a Russula delica voucher from the Pacific Northwest determined by Mary Berbee, Bart Buyck, and other reputable mycologists. So that’s my best best. Less than 98% identical are Russula brevipes, delica, and chloroides, so there are other good options.

It would be nice…
By: I. G. Safonov (IGSafonov)
2019-10-28 13:25:56 PDT (-0700)

…to have access to the ITS sequence so that BLASTn results can be carefully screened.

I
By: Eva Skific (Evica)
2019-10-28 13:16:11 PDT (-0700)
thought it was strictly a European mushroom