February 15, 2021
Happy Presidents’ Day team,
We’re staying in the same genus for this week’s mushroom which is Biscogniauxia marginata (formerly known as Hypoxylon marginatum and Nummularia discrete). Like B. atropunctata last week, this fungus is also a plant pathogen and causes what’s known as “blister canker” on woody plants in the family roseaceae – predominantly on apples and crab apples.1,2 This fungus was found on 1/21/2020 on a stick underneath the large hornbeam just north of muggers woods. There isn’t a lot of reliable data on this mushroom but it’s safe to say it can be found in eastern North America and Europe. The hockey puck like cankers are not actually mushrooms but are the stromata (plural of stroma, mycelium mat/body) of the fungus. If only I had sent this out yesterday we would’ve had a Stromata Sunday.
One interesting note is that both this and B. atropunctata have dark, heavily melanized, stroma. I thought this might mean they are “brown rot” fungi, which predominantly consume the cellulose in plant cell walls – where as “white rot” fungi consume the lignin. However, heavy melanin content is found in a lot of fungal pathogens as it helps them handle environmental stressors and promotes virulence.3 It can even help them resist antifungal drugs. Fascinating. The full scope of melanin’s use and benefits for fungi isn’t yet understood.
I know I ran a bit long today, but I’m at work today and just needed a break from working super-duper hard 😉
1) Blister canker | Horticulture and Home Pest News (iastate.edu)
2) Biscogniauxia marginata (free.fr)3) Eisenman, H.C., Greer, E.M. & McGrail, C.W. The role of melanins in melanotic fungi for pathogenesis and environmental survival. Appl Microbiol Biotechnol104, 4247–4257 (2020). https://doi.org/10.1007/s00253-020-10532-z