he strange ascomycete Cyttaria comprised of 11 species. Also unclear is species are obligate biotrophs the phylogenetic relationship of Cyttaria of trees in the genus Nothofagus to its closest fungal relatives, which, T(known as “Southern beech” but not along with its unusual compound fruit closely related to Northern Hemisphere bodies, specialized habit, and lack of cell beech; Southern beech are relatives wall chitin (having instead β-1-3-glucan) to witch hazel). Cyttaria species are (Oliva et al., 1986), further obscure its restricted to the Southern Hemisphere, phylogenetic affinities. The strange- inhabiting southern South America looking fungus, with an even stranger (Argentina and Chile) and southeastern growth habit, has long been a mystery to Australasia (southeastern Australia science but recently a number of studies including Tasmania, and New Zealand). have shed light on the taxonomy and The relationship of this fungus with its phylogeography of this fungus and its host remains unclear; if truly parasitic, it’s host. But I think I’m getting ahead of only weakly so—maybe it’s beneficial in myself. Such a noteworthy group of fungi some way. as this need a proper introduction! Britt A. Bunyard Cyttaria species are members of the It was Charles Darwin who first brought Photos courtesy of Giuliana Furci inoperculate discomycetes; the genus is this peculiar fungus to the mycological world’s attention. He chronicled (1839) and collected fruitbodies from large cankers on Southern beech trees during a stop at the southern tip of South America (Tierra del Fuego), during his voyage on the Beagle (for a review, see Schaechter, 2010). Darwin sent his collections to the esteemed mycologist Reverend Miles Berkeley who described the new genus Cyttaria (1842). Field notes about the ascocarp fruitbodies noted that the indigenous people there collected them as food. That’s right, those brightly colored fruitbodies are similar to those of morels. Both are apothecia, a sort of cup-shaped ascocarp, with sterile ridges separating the fertile areas. Harvard researchers Kristin R. Peterson and Donald H. Pfister in 2010 published a phylogeny of Cyttaria based on a combination of morphological data and DNA sequence analysis. They found evidence for a close relationship between the Cyttariales and members of the order Helotiales which includes the green stain fungus Chlorociboria, as well as Leotia, Ascocoryne, Bisporella, and Bulgaria (Wang et al., 2006a; 2006b). Furthermore, three major clades were identified within Cyttaria: one in South America hosted by subgenus Nothofagus, another in South America hosted by subgenera Nothofagus and Lophozonia, and a third in South America and Australasia hosted by subgenus Lophozonia, thus producing a non-monophyletic clade of South American species and a monophyletic clade of Australasian species, including monophyletic Australian and New Zealand groups. Expanding their investigation to the only hosts of Cyttaria FUNGI Volume 11:1 Spring 2018 59 60 FUNGI Volume 11:1 Spring 2018 spp. (Nothofagus spp.), the researchers fungi. Also, the association (parasitism, described them that way—golf balls found cophylogeny (Peterson et al., 2010b). commensal, mutualistic) has not been did not get dimples until the 1900s!). In other words, the evolutionary trees of clearly determined; it is possible the Each fruitbody is actually composed of the fungus and host tree overlap a great fungus benefits the tree in some unknown sterile fungal tissue, or stroma, in which deal. (Some discrepancies are explained by way (Gamundí and Lederkremer, 1989). apothecia are embedded. According host-jumping, extinctions, and speciation The symbiosis is readily noticed; infection to Peterson et al. (2010) the seemingly that also has occurred over time.) Thus, by the fungus results in visible trunk otherworldly-looking stromata “typically as Southern beech migrated around the and branch cankers. A typical mature have a fleshy-gelatinous consistency, Southern Hemisphere, the trees took their fruitbody of Cyttaria species consists but those of some species are gummy fungal passengers with them. of what may appear to be an orange or slimy. As the stromata develop, What is known about the association to very pale, pitted ascoma, somewhat apothecia form beneath a membrane that between Cyttaria species and Southern similar to a morel or a deeply dimpled envelopes the fruitbody. At maturity this beech? First off, not all species of golf ball (though Darwin, Berkeley, membranous ectostroma peels away to Nothofagus seem to be associated with the and contemporaries would have never reveal, depending on the species and the

FUNGI Volume 11:1 Spring 2018 61 stroma, 1–200 apothecia, each lined with And work best at ambient temperatures. asci.” Spore print is dark gray to black. As Lager yeasts are strange creatures as is the case with some other ascomycetes they work best under cold conditions (Xylaria comes to mind), prior to sexual and, it’s been reasoned, must come from spore production, the stromata of some cold climates. It was recently shown Cyttaria species can produce asexual that Cyttaria harioti harbors the yeast conidia, termed haploid mitospores Saccharomyces eubayanus which may (Minter et al., 1987). be source of cold tolerance in the lager A close examination of the asci reveal yeast, S. pastorianus (=S. carlsbergensis) them to be 8-spored and inoperculate (Libkind et al., 2011). How it found its way “with Bulgaria inquinans-type ascus to Europe and wound up in a beer tun is apices” (Mengoni, 1986) that stain blue still unclear but there have been centuries The beginning of agriculture in iodine. Ascomycete asci are either of trade between South America and and the domestication of operculate or inoperculate. Most Pezizales Europe, so it’s not the most far-fetched plants and animals are among have operculate asci; the spores are facet to this story of the most bizarre the most decisive events released through a lid-like structure, the mushroom of the Southern Hemisphere. in human history because operculum, at the tip of the ascus. In Strangely, S. pastorianus has never they triggered the rise of contrast, inoperculate asci have no lid, been isolated from the wild and depends civilizations and the attendant instead these fungi have a pore at the entirely on humans for its propagation. demographic, technological, ascus tip and the mature spore squeezes Weird, huh? I know. So … how did it and cultural developments. out through that pore. The photo of arise? Glad you asked. Pour yourself a The domestication of barley Sordaria superba shows the tips of two cold one, get comfy, and I’ll tell you. In in the Fertile Crescent led to inoperculate asci made visible with Congo a paper just published in the journal the emergence of the forebear red stain. Proceedings of the National Academy And what of the edibility of this fungus? of Science a multinational team of of modern beer in Sumeria Elio Schaechter, The Authority on all researchers led by Diego Libkind and 6,000 years ago. Beer and things microbial, recounted in FUNGI Chris Todd Hittinger have found that, other alcoholic beverages may (2014) that Darwin noted the natives during a global inventory of wild yeasts, have played a pivotal role in of Tierra del Fuego, the Yaganes, ate S. pastorianus was created through cementing human societies these mushrooms “although, oddly, they the hybridization of a S. cerevisiae ale through the social act and bypassed fresh specimens in favor of older, yeast with another, previously unknown rituals of drinking and by wizened ones. Some years ago, I came cryotolerant (cold tolerant—remember providing a source of nutrition, up with a possible explanation. Uniquely that lager beers are “cold-brewed”) medicine, and uncontaminated among mushrooms, Cyttaria have a Saccharomyces species. water. In Europe, brewing concentration of fermentable sugars … In nature, many different yeasts are gradually evolved during the could it be that [the Yanage] favored the found in the sap flows that exude from Middle Ages to produce ale- older specimens undergoing fermentation? wounds and cracks commonly seen on These people were surprisingly hardy; trees. Saccharomyces spp. are associated type beer, a process conducted they were very scantily dressed, yet living with oak trees (Fagaceae) in the by Saccharomyces cerevisiae under very harsh climatic conditions. Northern Hemisphere. Because species (“brewer’s yeast”), the same I posited that a little alcohol from of the genus Nothofagus (Southern species involved in producing fermented Cyttarias may have gone a beeches, also members of the Fagales) wine and leavened bread. long way towards good cheer.” Support of occupy the oak niche in the colder Lager-brewing arose in 15th this notion comes from the modern-day temperate regions of the Southern century Bavaria, gained broad people who live in this region and call Hemisphere, the research team acceptance by the late 19th the fruitbodies that fall from Southern reasoned this may be a good place century, and has since become beech llao-llao. Besides consuming them to look for undiscovered wild lager the most popular technique for outright, the fruitbodies are collected and yeasts. They focused on woodlands producing alcoholic beverages, fermented into a beverage called chicha containing populations of Nothofagus with over 250 billion dollars of de llao-llao. antarctica, Nothofagus dombeyi, But wait there’s more. Could chicha and Nothofagus pumilio, as well as global sales. Unlike most ales de llao-llao be the “mother of all beers?” the sugary fruitbodies of Cyttaria and wines, lagers require slow, Maybe. Here’s why. The wild source of associated with the trees. In their low temperature fermentations lager yeast has long been sought, and report, the team documents the that are carried out by it may have just been found growing isolation of that mystery yeast species cryotolerant Saccharomyces on Cyttaria fruitbodies (see sidebar). and designate it Saccharomyces pastorianus (formerly called Did I just blow your mind? Firstly, it is eubayanus because of its resemblance S. carlsbergensis). important to point out that ale yeasts to S. bayanus (a complex hybrid come from the environment where of S. eubayanus, S. uvarum, and S. modern beers were invented: Europe. cerevisiae found only in the brewing 62 FUNGI Volume 11:1 Spring 2018 environment). Populations of the Roy, R.N., from 1832 to 1836. London: fungus Cyttaria harioti. Experimental newly discovered S. eubayanus exist Henry Colborn. 615 p. Mycology 10: 150–156. in the chilly Nothofagus (Southern Gamundí, I.J., and R.M. Lederkremer. Peterson, K.R., D.H. Pfister, and C.D. beech) forests in Patagonia (way 1989. Los hongos andinopatagonicos Bell. 2010. Cophylogeny and down at the southern tip of South del genero Cyttaria. Sus hidratos de biogeography of the fungal parasite America—I know, not the first place carbono. Ciencia e Investigación Cyttaria and its host Nothofagus, the you think of when thinking of beer). 43: 4–13. Southern beech. Mycologia 102(6): Still, identifying the wild genetic Libkind, C., T. Hittinger, E. Valério, C. 1417–1425. stock of the cryotolerant yeast S. Gonçalves, J. Dover, M. Johnston, P. Peterson, K.R., and D.H. Pfister. 2010. pastorianus is necessary for resolving Gonçalves, and J.P. Sampaio. 2011. Phylogeny of Cyttaria inferred from the taxonomy and systematics of this Microbe domestication and the nuclear and mitochondrial sequence important species complex, and for identification of the wild genetic stock and morphological data. Mycologia understanding the key events that led of lager-brewing yeast. Proceedings of 102(6): 1398–1416. to the domestication of lager yeast. In the National Academy of Science USA Schaechter, E. 2010. Darwin and the contrast to extensive investigation into 108(35): 14539–14544. fermentable mushrooms of Tierra del domestication of crops and livestock, Mengoni, T.P. 1986. El aparato apical del Fuego. Fungi 3: 15. studies of domestication of eukaryotic asco de Cyttaria harioti (Ascomycetes- Wang, Z., M. Binder, C. Schoch, P.R. microbes have been all but nonexistent. Cyttariales) con microscopía fotónica Johnston, J.W. Spatafora, and D.S. Reference Cited y electronica. Bulletin of the Botanical Hibbett. 2006a. Evolution of helotialean Society of Argentina 24: 393–401. fungi (Helotiomycetes, Pezizomycotina): Berkeley, M.J. 1842. On an edible fungus Minter, D.W., P.F. Cannon, and H.L. a nuclear rDNA phylogeny. Molecular from Tierra del Fuego and allied Chilean Peredo. 1987. South American species Phylogenetics and Evolution 41: species. Transactions of the Linnean of Cyttaria, a remarkable and beautiful 295–312. Society of London 19: 37–43. group of edible ascomycetes. Mycologist Wang, Z., P.R. Johnston, S. Takamatsu, Darwin, C. 1839. Journal of researches 21: 7–11. J.W. Spatafora, and D.S. Hibbett. 2006b. into the geology and natural history of Oliva, E.M., A.F. Cirelli, and R.M. Toward a phylogenetic classification of the various countries visited by H.M.S. Lederkremer. 1986. Chemical the Leotiomycetes based on rDNA data. Beagle, under the command of Capt. Fitz composition of the cell wall of the tree Mycologia 98: 1065–1075.

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