Some Thoughts on the Fungus (and Humans) Among Us

SO, ANYWAY, I am putting THIS post here because I like it, at least (and one gets to do that with a BLOG) because I am wondering if it isn’t possible (cutting to the chase, here) that, yes, in fact, leaf rust disease attacks the same trees that produce coffee we like to drink BECAUSE those trees “taste good” to them as well. I know that by implying that the fungi cells in question [Hemileia vastatrix] have a sense of “taste” I may be chided or even ridiculed for grossly over-simplifying what is going on when a coffee tree is infected by this organism; not to mention taking anthropomorphism to a whole new level, well, PHYLUM, actually… But if there is any link between what types of trees Hemileia vastatrix likes to infect and the trees which produce the best tasting coffee (to us humans) then this would mean that it is less likely that searching for a rust-resistant hybrid is going to be the solution the coffee industry needs to address to the very serious leaf rust issue we are facing today.

The basis for this argument/conjecture stems from the point that one of the symposium lecturers at the SCAA’s 5th Annual Symposium made: that we, as Homo sapiens, share 50% of our genetic material with Hemileia vastatrix, and, therefore, “we” MIGHT share a distant similarity or two.

Here following is the post I wrote after listening to a lecture given by Dr. Mary Catherine Aime at the 5th Annual Symposium of the Specialty Coffee Association of America (it is also posted on their site as well, I am pleased to note!) . If it does not offer the basis for a valid discussion based on the biology, I hope it will at least provide some comic relief. And, in that regard, one must ask, can fungus laugh?


Tuesday, April 10, 2013, at the SCAA’s fifth annual Symposium, was not the first time that I’d heard we’re related to fungi.  Forty years ago at UC Berkeley, my biology professor, whose name I cannot remember, noted, “The reason systemic mycoses [that is, fungal infections] are so hard to kill is because we’re related, and a lot of the things that will kill fungal infections will also kill us [and other members of the Animal Kingdom].” He then discussed why it was so much easier (at that time, at least) to knock out a bacterial infection because the cellular structure was so much different from ours and those of fungal organisms. Poisons that kill bacteria (antibiotics) tend not to hurt us.


The idea that “we” could be related fascinated me and I would think about it every now and then…until one rather pleasantly warm and blurry night about twenty years later when I was at dinner with some friends talking about people who weren’t at the table and then we moved on, with even more ruthless abandon, to ourselves. The repartee quickly outpaced me as the apt insults and incisive sarcasm volleyed around the table landing flesh wounds to our psyches, but nothing mortal. I was just impaired enough to pull myself back a bit, look up and down the table and intone to myself, “Yep, like yeast, only meaner.”  I have since, over the years, recalled my self-authored aphorism many times when confronted by especially petty but persistent and effective maliciousness (yes, on MY part AND others): I would think to myself, we are each, after all, little different than a nasty fungal infection, what can one expect? (And, it occurs to me now, that we all, at that table, could owe our jolly moods, as well, to that beloved produce of our genetic half brother’s and sister’s: ethanol.)


Then, on the first day of Symposium 2013, Tuesday morning, when Dr. Mary Catherine Aime pointed out (for the second time in my life) that we (animals, mammals, people) bear a great deal of genetic similarity to fungi, I remembered my biology professor, my extrapolation upon his observation regarding fungi-cides, and I smiled.


Later, during one of the breaks, I was talking about the coffee rust disease with someone with a lot of experience working with coffee farmers who were constantly battling the disease.  He felt that we shouldn’t be counting too much on being able to finesse the genetics of the coffee plant such that it will be able to resist rust while still producing coffee that tastes good.  My friend believes that fungicides and keeping the trees quarantined from the disease, while not foolproof or ideal, are essential short-term fixes while we wait for a real solution. “Look,” he said, “we’ve all tasted the coffee from these rust resistant varieties and none of it tastes good…I don’t think we’re going to find a good tasting, rust-resistant coffee.” Whether or not my friend is correct did not prevent a scary thought from crossing my mind: what if, since we are so similar, that the coffee rust fungi “prefers” to infect high quality coffee trees just as humans prefer drinking the coffee they produce? Maybe those varieties don’t just taste good to us humans but to our fungal friends as well.


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