Across much of the northern hemisphere, there grows a type of mushroom called Suillus. This fungus is a member of a group that forms ectomycorrhizas- tiny symbiotic organs on the root tips of forest trees. Many tree species need these fungi, so much so that they would starve to death without them. Although most ectomycorrhizal fungi will form these organs with many different kinds of host trees, Suillus only likes trees from a single family called the Pineaceae (including Pines, Larch and Douglas fir, among others).
If you mention Suillus to the post doc who had a large hand in getting me started on this project, his eyes widen, and his face takes on an expression that can only be interpreted as love. Scientifically, I couldn’t ask for a better system to work in; it allows me to ask questions that are both focused and mechanistic and broad and ecological. Plus, I get to split my time between the lab bench, the computer and the woods, which is important for someone sporting my specific combination of neuroses.
However, at the risk of sounding ungrateful, and as anyone I’ve talked to about my thesis already knows; I hate Suillus.
The genus name, Suillus, derives from the Latin word sus, meaning 'pig'. The common name, 'Slippery Jacks', comes from the viscous slime that covers the mushroom’s caps when they get wet. The species’ names are even lovelier. Suillus americanus, for example, is colloquially known as the “chicken fat mushroom”, because that’s exactly what that shit looks like.
The thick mucosal slime that coats the mushroom is a bile-yellow-green. Everything seems to stick to this slime; soil, pine needles, dead insects. When you collect the mushrooms, the slime sticks on your fingers, clothes, collecting basket, your macro camera lens . . . When the mushroom cap dries, the goo shrinks down, incasing the dirt and detritus into something resembling an ill advised mushroom camo helmet. Rather than gills, the mushrooms have yellow pores on the underside of the cap. These pores bruise brown when touched and are often partially covered by a thin, rubbery, transparent skin called a ‘partial veil’. To collect their spores, the caps are cut from the stipe and placed on an iron mesh covering a glass container, where in just a few hours, a cascade of enzymes break down the tissue, turning the once bright yellow pores into a black liquid. Its not enough that the melting mushrooms smell like the bottom of a forgotten compost container, the caps are also frequently (more often than not) filled with tiny larva, and as the mushrooms rot, maggots fall through the mesh and are left to drown in the spore slurry.
I could add other examples to the above description of Suillus subaureus (exuding pigments and unknown extraction inhibitors which have made sequencing it’s genome super fun, or fruiting in such abundance that my single field site, over two hours away, produced all of 1 sporocarp last year) but I will refrain. Because today, I believe that there may be hope for Suillus and myself.
As it turns out, the elusive, slimy, maggoty, foul smelling, bile yellow nemesis that I’ve dedicated the last two (and next three) years to, is actually capable of producing indisputably adorable little mycorrhizas. And after 7 months, and hundreds of sadly sacrificed baby trees, I was finally able to synthesize them on Oak; confirming the long-standing rumor that S. subaureus, unlike all other species of Suillus fungi, can form mycorrhizae on trees outside of the Pineaceae (see above picture for mycorrhizal cuteness).
In addition, after avoiding putting my face anywhere near the subaureus cultures I’ve been coddling for the last 18 months, one of our post docs inspired me to sniff it (the species he works with oddly smells exactly like coconuts). In truth, S. subaureus in culture smells nothing like anoxic compost. It actually smells just like (again, oddly, I know). . . warm butter on mandarin oranges. . . which I have never had. . but might have to try.