Tag Archives: Fungi

Friday Fellow: Orange Peel Fungus

by Piter Kehoma Boll

Fungi show a variety of different fruiting bodies and they are almost always named based on what those fruiting bodies look like. This is the case of today’s fellow as well. Its scientific name is Aleuria aurantia and it is commonly known as the orange peel fungus. Due to English ambiguous language, such a name could mean a fungus that grows on orange peels as well, but that is not the case, as such a species is named green mold.

The orange peel fungus is found throughout the Holarctic region, i.e., North America, Europe and Northern Asia, and eventually elsewhere, probably due to human-driven dispersal. Its main habitat includes opean areas near conifer forests, where it lives as a saprotrophe, i.e., a decomposing fungus with the mycelia scattered through the soil.

Orange peel fungus in France. Photo by David Renoult.*

The cup-shaped fruiting bodies appear more often in autumn. They have a strong orange color caused by carotenoids, especially β-carotene, γ-carotene and aleuriaxanthin. At first they are small and very regular, but grow up to 6 cm in diameter, when their structure often becomes irregular or torn apart, resembling pieces of orange peel thrown on the ground. The spores that they produce remain ungerminated in the soil until spring, when they start to grow. The cold temperatures of winter seem to be necessary for the spores to germinate, as spores in laboratory cultures only germinated successfully after remaining frozen for about 3 months.

The orange peel fungus has been a target species for pharmacological studies due to the presence of a lectin called Aleuria aurantia lectin (AAL). Lectins are a group of proteins that bind to sugars or sugar groups of other molecules such as glycoproteins and glycolipids. They are found in all groups of organisms and have different functions. In animals, for example, they are important in cell adhesion. They connect to glycoproteins on the cell membrane and tie neighbor cells to each other, preventing tissues to fall apart.

Flattened and broken fruiting bodies resembling orange peel in the United States. Credits to iNaturalist user schwee.*

In many parasitic fungi, bacteria and viruses, lectins are important to recognize the host. They also seem to have a role during the production of spores in fungi. AAL from the orange peel fungus binds to fucose, a sugar that is commonly found on the surface of cells in mammals, insects and plants as part of their glycoproteins. The name fucose comes from the fact that this sugar forms the polysaccharide fucoidan found in several species of brown algae.

AAL has several practical uses. Due to its fucose-binding behavior, it can be used to detect the presence of fucose in different cells. Fucose is also related to some types of allergies and AAL has been studied as a potential compound to develop new antiallergics.

Other than its pharmacological properties, the orange peel fungus is also edible, though not that popular as food. Its fruiting bodies can be eaten fresh or dried for storage. Due to the presence of carotenoids, the orange peel fungus has potential antioxidant properties, although studies on its nutritious value seem to be lacking.

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References:

Fukumori F, Takeuchi N, Hagiwara T, Ohbayashi H, Endo T, Kochibe N, Nagata Y, Kobata A (1990) Primary structure of a fucose-specific lectin obtained from a mushroom, Aleuria aurantia. Journal of Biochemistry 107(2):190–196. doi: 10.1093/oxfordjournals.jbchem.a123024

Ogawa S, Nagao H, Ando A, Nagata Y (2000) Enhancement of ascospore germination from Aleuria aurantia after cold storage. Mycoscience 41:287–289. doi: 10.1007/BF02489686

Ogawa S, Nakajima E, Nagao H, Ohtoshi M, Ando A, Nagata Y (1998) Synthesis of a Lectin in Both Mycelia and Fruit Bodies of the Ascomycete Mushroom Aleuria aurantia. Bioscience, Biotechnology, and Biochemistry 62(5):915–918. doi: 10.1271/bbb.62.915

Roth-Walter F, Schöll I, Untersmayr E, Fuchs R, Boltz-Nitulescu G, Weissenböck A, Scheiner O, Gabor F, Jensen-Jarolim E (2004) M cell targeting with Aleuria aurantia lectin as a novel approach for oral allergen immunotherapy. Journal of Allergy and Clinical Immunology 114(6):1361–1368. doi: 10.1016/j.jaci.2004.08.010

Seaver FJ (1914) North American Species of Aleuria and Aleurina. Mycologia 6(6):273–278. doi: 10.1080/00275514.1914.12020977

Singh U, Bhatt RP, Stephenson SL, Uniyal P, Mehmood T (2017) Wild edible mushrooms from high elevations in the Garhwal Himalaya—II. Current Research in Environmental & Applied Mycology 7(3):208–226. doi: 10.5943/cream/6/2/6

Węgiel J, Kohlmünzer S (2001) Mycelial culture of the fungus Aleuria aurantia and some of its metabolites. Pharmaceutical Biology 39(2):108–112. doi: 10.1076/phbi.39.2.108.6249

Wimmerova M, Mitchell E, Sanchez JF, Gautier C, Imberty A (2003) Crystal structure of fungal lectin six-bladed β-propeller fold and novel fucose recognition mode for Aleuria aurantia Lectin. Journal of Biological Chemistry 278:  27059-27067. doi: 10.1074/jbc.M30264220

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Friday Fellow: Versatile Funnel Glomus

by Piter Kehoma Boll

It is time to go back to the micoscopical world and present the wonders that it contains. Today the chosen species is Funneliformis mosseae, which, as always, lacks a common name. I, therefore, decided to call it the versatile funnel glomus.

The versatile funnel glomus is a fungus of the division Glomeromycota. These fungi are characterized by forming an endosymbiotic relationship with plants through structures called arbuscular mycorrhizas, or AMs for short. This special kind of mycorrhiza is formed with the fungus growing inside the tissues and cells of plant roots. It is known that around 80% of all vascular plant families contain AMs.

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Spores of the versatile funnel glomus on tomato roots. Photo by Wikimedia user Samson90.

Our species, the versatile funnel glomus, is considered one of the most common fungi associated to plant roots. Found worldwide, it can form AMs with many different plants, including many important cultivars, such as maize, onion, tomato and many others.

Funneliformis_mosseae_spore

A single spore of the versatile funnel glomus showing the funnel-shaped base to the right. Photo extracted from Schüßler & Walker (2010).

Since the versatile funnel glomus lives inside the root tissues and cells, it is not usually conspicuous, but it can be easily identified through its spores, which are about 0.2 mm in diameter and grouped inside sporocarps. The base of the spore has a funnel shape, this being the reason for the name Funneliformis.

The association of the versatile funnel glomus with plants increases nutrient uptake by plants and can also help them cope with environments contaminated with heavy metals, such as lead, by absorbing part of the contaminant, thus reducing its deleterious effect on the plants.

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References:

Citterio, S.; Prato, N.; Fumagalli, P.; Aina, R.; Massa, N.; Santagostino, A.; Sgorbati, S.; Berta, G. (2005) The arbuscular mycorrhizal fungus Glomus mosseae induces growth and metal accumulation changes in Cannabis sativa LChemosphere 59(1): 21–29.

EOL – Encyclopedia of Life. Glomus mosseae. Available at < http://eol.org/pages/988675/overview >. Access on July 17, 2018.

Schüßler, A.; Walker, C. (2010) The Glomeromycota. A species list with new families and new genera. Gloucester, UK.

Xu, Z.; Ban, Y.; Yang, R.; Zhang, X.; Chen, H.; Tang, M. (2016) Impact of Funneliformis mosseae on the growth, lead uptake, and localization of Sophora viciifoliaCanadian Journal of Microbiology 62(4): 361–373.

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Friday Fellow: Pear Rust

by Piter Kehoma Boll

Beautiful and deadly, today’s fellow appears during spring as gelatinous orange projections coming out of juniper trees in Europe and North America. Its name is Gymnosporangium sabinae, commonly known as the pear rust.

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The jelly-like horns of the pear rust on a juniper tree. Photo by Mark Sadowski.*

The pear rust is a basidiomycete, i.e., a fungus of the phylum Basidiomycota, therefore related to the common mushrooms, but belonging to a different class, the Puccioniomycetes.

During winter, the pear rust remains in a resting state inside branches and twigs of juniper trees. After wet days in spring, the fungus sprouts and appears as horn-like growths covered by an orange gelatinous mass, which are called telia. The telia produce wind borne spores called teliospores that can infect pear trees.

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The pear rust on pear leaves. Photo by Jan Homann.

Once reaching the pear tree, the teliospores germinate and infect the leaves of the new host. The infection appears in summer as rust-colored spots on the leaves, hence the name pear rust. In heavily infected plants, the effects of the pear rust can be severe, sometimes causing the plant to lose all its leaves.

In pear trees, the fungus produce reproductive structures known as aecia. They come out from the underside of pear leaves and produce spores called aeciospores, which are able to infect new juniper trees.

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The aecia coming out of the rust on a pear tree. Photo by H. Krisp.**

Due to the economic importance of pear trees to humans, the pear rust is a species of great concern. Some countries have policies intended to reduce the spread of the disease, such as preventing transportation of juniper trees from areas known to have the fungus to areas in which it is unknow. In areas where the fungus exist, the solutions to reduce the damage include the use of chemical fungicides, the removal of infected branches in juniper trees and sometimes the removal of any juniper tree around the areas where pear trees are cultivated.

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References:

Fraiture, A.; Vanderweyen, A. (2011) Gymnosporangium sabinae: such a beautifiul disease. Scripta Botanica Belgica 11: 193–194.

Ormrod, D. J.; O’Reilly, H. J.; van der Kamp, B. J,; Borno, C. (1984) Epidemiology, cultivar susceptibility, and chemical control of Gymnosporangium fuscum in British Columbia. Canadian Journal of Plant Pahology6: 63–70.

Wikipedia. Gymnosporangium sabinae. Available at < https://en.wikipedia.org/wiki/Gymnosporangium_sabinae >. Access on April 27, 2018.

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Friday Fellow: Brown spot of maize

by Piter Kehoma Boll

I’ll continue the parasite trend from last week, but this time shifting from human parasite to maize parasite, and from a prokaryotic to a eukaryotic parasite. So let’s talk about Physoderma maydis, commonly known as the brown spot of maize or brown spot of corn.

The Brown spot of maize is a fungus of the division Blastocladiomycota that infects corn (or maize) plants. Its common name comes from the fact that it causes a series of brown spots on the leaves of an infected plant.

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The brown spots seen on this corn leaf are due to an infection by Physoderma maydis. Credits of the photo to Clemson University – USDA Cooperative Extension Slide Series.*

The life cycle of the brown spot of maize is as complex as that of many fungi. The infection of the plants occur through spores that remain in the soil during winter and are carried to the host by the wind, germinating in the rainy season. The germinated spores produce zoospores, flagellated spores able to swim. Swiming through the maize leaf, the zoospores infect single cells and produce zoosporangia at the surface of the leaf. The zoosporangia release new zoospores that infect new cells. In late spring and summer, the zoospores produce a thallus growing deep inside the maize leaf that infects many cells and produces thick-walled sporangia. After the plants dies and the leaves become dry and broke, the sporangia are released and reach the soil, where they wait for the next spring to restart the cycle.

The brown spot of maize is a considerable problem for maize crops in countries with abundant rainfall. Heavy infections may kill the maize plant or severely reduce its fitness before the ears are ready to be harvested. Although fungicides may help in slowing down the infectio throughout the crops, one of the most efficient ways to reduce the damage is to destroy, usually by fire, the remains of the last harvest.

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References:

Olson, L. W.; Lange, L. (1978) The meiospore of Physoderma maydis. The causal agent of Physoderma disease of maize. Protoplasma 97: 275–290. https://dx.doi.org/10.1007/BF01276699

Plantwise Knowledge Bank. Brown spot of corn (Physoderma maydis). Available at: < http://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=40770&gt;. Access on Agust 7, 2017.

Robertson, A. E. (2015) Physoderma brown spot and stalk rot. Integrated Crop Management News: 679. http://lib.dr.iastate.edu/cropnews/679/

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Friday Fellow: Baker’s Yeast

by Piter Kehoma Boll

Living along humans for centuries, today’s Friday Fellow is certainly one of the most beloved fungi. Scientifically known as Saccharomyces cerevisiae, its common names in English include baker’s yeast, brewer’s yeast or ale’s yeast.

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Saccharomyces cerevisiae under the scanning electron microscope. Photo by Mogana Das Murtey and Patchamuthu Ramasamy.*

Under the microscope, the cells of this single-celled species are ellipsoid or sphere-shaped and usually show small buds from new cells growing from the larger one. But you may have seen this species being sold as tablets or grains in the supermarket, as they are used to make bread and many alcoholic bevarages, such as wine and beer, but the baker’s yeast is much more interesting than just that.

450px-d094d180d0bed0b6d0b6d0b8_d181d183d185d0b8d0b5_d0b1d18bd181d182d180d0bed0b4d0b5d0b9d181d182d0b2d183d18ed189d0b8d0b5_-_rapid-rise_yeast

Grains of dried but yet alive baker’s yeast as it is sold commercially.

The cells of the baker’s yeast occur naturally on ripe fruits, such as grapes, and this was likely the original source of the strains currently cultivated by humans. The yeast reaches the fruits through many wasp species that have it growing in their intestines, an ideal environment for the fungus’ sexual reproduction.

As it is easily cultivated in the lab and has a short generation time, the baker’s yeast has become one of the most important model organisms in current biological studies. It was, in fact, the first eukaryotic organism to have its whole genome sequenced more than 20 years ago.

Saccharomyces_cerevisiae

Saccharomyces cerevisiae growing on solid agar in the lab. Photo by Conor Lawless.**

More than giving us food and drink, this amazing yeast has increased our understanding of gene expression, DNA repair and aging, among many other things. Live long the yeast!

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References:

Giaever, G.; Chu, A. M.; Ni, L.; Connelly, C. et al. (2002) Functional profiling of the Saccharomyces cerevisiae genome. Nature 418 (6896): 387-391.

Herskowitz, I. (1988) Life cycle of the budding yeast Saccharomyces cerevisiae. Microbiological Reviews 52 (4): 536-553.

Wikipedia. Saccharomyces cerevisiae. Available at < https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae >. Access on July 25, 2017.

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Friday Fellow: Gray Mold

by Piter Kehoma Boll

Today’s Friday Fellow will show you how beauty is only a matter of perspective. Being an ascomycete fungus, it is commonly known as gray mold and is usually found growing on decaying vegetables, especially fruits such as the strawberry in the photo below:

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Gray mold growing on a strawberry. Most people would not see it as a beautiful image. Photo by Wikimedia user Rasbak.*

The gray mold has a controversial biological nomenclature, as many other fungi. The most common name is Botrytis cinerea used for its asexual stage (anamorph), which is the most common. Its sexual stage (teleomorph) is known as Botryotina fuckeliana. I guess this issue, which was common in naming fungi with rare or unknown occurrences of sexual stage, has already been settled, but as I’m not a taxonomist of fungus, I cannot speak much on the subject.

More than only having a controversial name, this fungus has also a controversial interaction with humans. It is a notable pest in wine grapes and may lead to two different infections on them. One of those is called “grey rot” and happens under wet conditions, leading to the loss of the grapes. The other is called “noble rot” and is a beneficial form of the infection that happens when the wet condition is followed by a dry one and produce a fine and sweet vine due to the concentration of sugars in the grape.

Out of the vine world, however, the gray mold is not something that you want growing on your crops. As as it attacks more than 200 species, many of them being important food crops, there is a big interest in developing strategies to reduce the damage it causes. And these strategies include the use of pesticides, plant essential oils or even other organisms that may parasitize the gray mold.

But one cannot deny that if you look closer, even the gray mold is beautiful:

Botrytis_cinerea

A beautiful tiny forest of gray mold on a strawberry. Photo by Macroscopic Solutions.**

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ResearchBlogging.orgReferences:

Wikipedia. Botrytis cinerea. Available at <https://en.wikipedia.org/wiki/Botrytis_cinerea&gt;. Access on June 2, 2017.

WILLIAMSON, B., TUDZYNSKI, B., TUDZYNSKI, P., & VAN KAN, J. (2007). Botrytis cinerea: the cause of grey mould disease Molecular Plant Pathology, 8 (5), 561-580 DOI: 10.1111/j.1364-3703.2007.00417.x

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Friday Fellow: Common Stinkhorn

by Piter Kehoma Boll

Today things are getting sort of pornographic again. Some time ago I introduced a plant whose flowers resemble a woman’s vulva, the asian pigeonwing, and now is time to look at something of the other sex. And what could be better than the shameless penis? That’s the translation of the scientific name of this mushroom, Phallus impudicus, whose common name in English is much more discrete: common stinkhorn.

Phallus_impudicus2

Standing proud and shameless. Photo by flickr user Björn S…*

Found throughout Europe and parts of North America in deciduous woods, the common stinkhorn is easily recognizable for its phallic shape and even more for its foul smell that resembles carrion. This odor attracts insects, especially flies, that carry the spores away. This is a different method from the one used by most fungi, which simply release the spores in the air. Some people may mistake the common stinkhorn for morels (genus Morchella) but the two are completely unrelated, being from different phyla.

Despite the foul smell, the common stinkhorn is edible, especially in its first stages of development, when it resembles an egg. Due to its phallic shape, it is also seen as an aphrodisiac in some culture, as it is common with genitalia-shaped lifeforms.

Phallus_impudicus3

The immature fruiting body of Phallus impudicus is the most commonly eaten form. Photo by Danny Steven S.*

The common stinkhorn seems to have some anticoagulant properties and can be used for patients susceptible to thrombosis in the veins, such as patients treating breast cancer.

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ResearchBlogging.orgReferences:

Kuznecov, G., Jegina, K., Kuznecovs, S., & Kuznecovs, I. (2007). P151 Phallus impudicus in thromboprophylaxis in breast cancer patients undergoing chemotherapy and hormonal treatment The Breast, 16 DOI: 10.1016/s0960-9776(07)70211-4

SMITH, K. (2009). On the Diptera associated with the Stinkhorn (Phallus impudicus Pers.) with notes on other insects and invertebrates found on this fungus. Proceedings of the Royal Entomological Society of London. Series A, General Entomology, 31 (4-6), 49-55 DOI: 10.1111/j.1365-3032.1956.tb00206.x

Wikipedia. Phallus impudicus. Available at <https://en.wikipedia.org/wiki/Phallus_impudicus&gt;. Access on March 7, 2017.

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