Mushrooming at Mt Rainier
By Stuart Graham
It’s 5 am at Mount Rainier National Park and, through a combination of jetlag and panic at the possibility of not collecting all my samples before leaving for a conference next week, I am wide awake. As the first light of dawn begins to strike the tree tops, I drive with my trusty unpaid field intern (spouse) to the Paradise Visitor Center and we hike out to my field sites armed with a soil knife, a checklist, sharpies and a backpack full of Ziploc bags.
Our goal is to sample the roots of subalpine fir trees. These beautiful conifers sport blueish green needles, smell like Christmas, and grow in subalpine meadows surrounded by a kaleidoscope of wildflowers. However, my research focuses on the ecological interactions that play out just below this idyllic scene – the fungi that grow on subalpine fir roots, providing their tree hosts with nutrients in exchange for sugars. On arrival at each tree, I use my soil knife to dig out a half gallon of soil and roots, while my unpaid field intern stays on the trail ready to present my research permit to any conscientious environmental stewards that may question why I am leaving the trail (usually by yelling “GET OUT OF THE MEADOWS!”)
Back at the university greenhouse, I carefully wash all the soil away from my root samples before drying them in preparation for DNA extraction. By sequencing the fungal DNA on my root samples and comparing them to sequence data published by other fungal researchers, I will be able to identify the fungal species growing on the subalpine fir roots. However, one potential problem with this protocol is that the half gallon of soil I sampled at each tree may not contain all the fungi that are growing on the tree’s roots.
To see if this problem occurred, I returned to the field sites in the fall with Lauren Dorsch (an undergraduate researcher and experienced mushroom grower in our lab) to survey for mushrooms at my field sites. Mushrooms are spore dispersal structures of fungi (think of trees letting their pollen blow in the wind) and grow out of the main body of the fungus that lives underground. Therefore, any species we find as mushrooms should also appear in the DNA data. Unfortunately, because not all fungi produce conspicuous mushrooms and many fungi don’t produce mushrooms every year, a mushroom survey could not replace the more expensive DNA sequencing method. The mushroom survey was a lot of fun. This fall was a great season for mushrooming and we found >100 species!
Stuart is a 4th year in Janneke Hills Ris Lambers Lab
