Umbelopsis ramanniana

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Umbelopsis ramanniana
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Mucoromycota
Order: Mucorales
Family: Umbelopsidaceae
Genus: Umbelopsis
Species:
U. ramanniana
Binomial name
Umbelopsis ramanniana
(Möller) W.Gams

Umbelopsis ramanniana is a common and abundant soil fungus. Although the ecological role of this fungus in natural ecosystems is not yet known, it is a cosmopolitan saprotroph in soil, forest leaf litter, in animal dung, and on the spore-producing bodies of ascomycete fungi. Umbelopsis ramanniana has also been found growing as an endophyte within xylem tissue of both healthy and declining conifers, but its exact effect on the plant hosts is unknown. Umbelopsis ramanniana is a representative of a unique group of zygomycete fungi that is distinct from the Mucoromycotina and Mortierellomycotina and instead forms an early diverging lineage within the Mucoralean fungi. Umbelopsis ramanniana is important from a biochemistry and biotechnology perspective because it is highly tolerant to fungicides of benomyl group, and it is oleaginous (it regularly produces oils). Expression of Umbelopsis ramanniana diacylglycerol O-acyltransferase 2A in seed increases oil in soybean without reduction of other important yield parameters. This increase in oil can potentially add over $1 billion to the annual value of soybean crops. [1]

Contents

Morphology

The species is a part of a complex phylogeny and classification, but the group this species is in differs from others in the order Mucorales by their sporangial structure, their spore shape and size, as well as in their dichotomously branched hyphae.

The sporangial structure is generally branched, producing sympodially proliferated sporangiospores. The spores are tinted pink (though some discussion has been on whether the pigmentations come from the spores, the sporangium itself, or even from the spore drop from the evanescent sporangial wall). [2]

Another characteristic morphological feature is the variation of the sporangiospore shape and size. The shapes vary from subglobose, rounded oblong, and ellipsoidal. The spore sizes vary from 2.2-3.9 µm by 1.3-2.0 µm. The wide ranges are characteristic of the species, but the three sub clades have been shown to account for that difference, each with their own ranges (Ogawa et al. 2005). The variation in the spore shape is thought to be a result of packing spores in a rigid sporangial wall. This prevents the development of round spores when they come to maturity, though differences in this effect are seen throughout the subclades (Tokumasu et al. 1990). U. ramanniana has been observed to have microchlamydospores, ranging from 4.9 ± 0.4 – 9.1 ± 0.8 µm, as well as the potential for macrochlamydospores, though not observed in all subclades. The chlamydospores have been observed to be filled with lipids. Umbelopsis ramanniana is not known to form any sexual structures, and are lacking in zygospores. [3]

The species is further characterized by its velvety colonies, a rudimentary columella being subglobose to flattened, and is lacking in the garlic-like odor that is common in the Mortierella isabellina-Group that U. ramanniana was originally thought to belong to.

General ecology

As of today, the exact ecological role of this fungus is not completely understood. It is a common soil saprobe, but has also been observed in other locations. It has been recorded in Great Britain, Hong Kong, Ireland, Kerala, Mauritius, New Zealand North, Ontario, Peninsular Malaysia, Queensland, Sri Lanka, Sweden, Victoria, and throughout the US. The most prevalent studies have shown Umbelopsis ramanniana to be present in leaf litter, animal dung, on the roots and within the xylem of some conifers, and on spore producing bodies of some ascomycetes including the ascocarp of Peziza species.

Specifically, in reference to the roots and xylem tissue of some trees, it has been observed within the soil in the root zone, with an affinity for fine roots, as well as within root core samples as an endophyte of certain conifers, including Picea abies and the Ponderosa pine. A study by Hoff et al. [4] in 2004 researched the soil mycology before and after a change in the soil environment, in this case a forest fire, to see how the fungal populations changed. U. ramanniana was one of the first to bounce back, with affinity for the ponderosa pine, leading the authors to believe that it is a common endophyte and soil saprobe that is favored by disturbance in a dry environment. [5]

Also, the spores of U. ramanniana have been found on the bodies of mites, along with many other genera. There seems to be no apparent symbiosis. It simply seems that the spores hitch a ride, and the mite is a simple vector for the spore dispersal of multiple ubiquitous fungi. [6]

Human relevance

Umbelopsis ramanniana is quite relevant to biology and human activity today due to both its high tolerance to benomyl group fungicides, and the oleaginous nature of the fungus. When isolating fungi from field or mixed samples, scientists often use an isolating medium containing benomyl fungicides, which constrict the growth of some fungi while having little to no effect on other genera. This allows for preferential colonization and the isolation of different strains for identification and research purposes. With U. ramanniana’s tolerance to this medium, it is more easily isolated, identified, and cultured for research and production purposes.

Beyond its ease of isolation and culture, the fungus is also oleaginous – it produces oil. It contains the gene diacylglycerol acyltransferase 2A, which is what codes for the oil production. Scientists have created a codon-optimized version of this gene that is introduced into soybeans and maize in order to increase the oil content of the oilseeds. Soybean production and processing alone accounts for 30% of vegetable oil used for food, feed, and industrial applications. It is first on the list of sources of lipids in food and biofuels, with maize coming in second. In these crops, most often there is an inverse relationship between oil and both protein and yield. As oil content is increased, yield and protein levels decrease. This is undesirable in large scale production, but the invention of the oil transgene allows produces to modulate one pathway without affecting the other. In soybeans, this gene increased oil content 1.5% by weight in mature seed, without any decrease in yield or protein synthesis. This is a huge step forward for the oilseed industry ( [7] [8] ).

Taxonomy and phylogeny

Umbelopsis ramanniana was first described by MÖLLER in 1903 under the name Mucor ramannianus, however today it is classified as Umbelopsis ramanniana (MÖLLER) W. Gams 2003. The name has gone through many changes from MÖLLER to Gams, and synonyms of Umbelopsis ramanniana include: Micromucor ramannianus (MÖLLER) Arx 1984, Mucor ramannianus MÖLLER 1903, Mortierella ramanniana (MÖLLER) Linnem 1941, Mortierella ramanniana var. ramanniana (MÖLLER) Linnem 1941, Mucor ramannianus var. ramannianus MÖLLER 1903, and Micromucor ramannianus var. ramannianus (MÖLLER) Arx 1984. As of today, there are no well-known or preferred common names.

U. ramanniana's classification is structured as follows: fungi > Zygomycota > not assigned > Mucorales > Umbelopsidaceae > Umbelopsis > U. ramanniana. It was originally through to be in the Mucoromycotina, however through genetic analysis has now been separated from it as well as Mortierellomycotina. It has two varieties that have been determined by its variable sporangial and zygospore structures; these two varieties are U. ramanniana var. ramanniana, and U. ramanniana var. angulispora. The latter is described as a variety due to the angular shape of its spores, thought to be due to the pressure of the rigid sporangial wall. [9]

The order Mucorales was first studied by scientists in the late 1800s, with a large amount of that research being done in Europe, but some in the southeastern United States. The zygomycete Umbelopsis ramanniana was first located as a ubiquitous soil saprobe in these areas of the world, as well as found in dung. As of today, it is recognized as within a polyphyletic group of Umbelopsis, but is thought to comprise three different intraspecific groups, based on genetic and phylogenetic research. [10] Multiple phylogenetic trees have been created and published to show both the characterization of U. ramanniana and the three sub-clades. [11] [12]

Related Research Articles

<span class="mw-page-title-main">Zygomycota</span> Division or phylum of the kingdom Fungi

Zygomycota, or zygote fungi, is a former division or phylum of the kingdom Fungi. The members are now part of two phyla: the Mucoromycota and Zoopagomycota. Approximately 1060 species are known. They are mostly terrestrial in habitat, living in soil or on decaying plant or animal material. Some are parasites of plants, insects, and small animals, while others form symbiotic relationships with plants. Zygomycete hyphae may be coenocytic, forming septa only where gametes are formed or to wall off dead hyphae. Zygomycota is no longer recognised as it was not believed to be truly monophyletic.

<span class="mw-page-title-main">Dothideomycetes</span> Class of fungi

Dothideomycetes is the largest and most diverse class of ascomycete fungi. It comprises 11 orders 90 families, 1,300 genera and over 19,000 known species. Wijayawardene et al. in 2020 added more orders to the class.

<span class="mw-page-title-main">Mucorales</span> Order of fungi

The Mucorales is the largest and best-studied order of zygomycete fungi. Members of this order are sometimes called pin molds. The term mucormycosis is now preferred for infections caused by molds belonging to the order Mucorales.

<i>Mortierella</i> Genus of fungi

Mortierella species are soil fungi belonging to the order Mortierellales within the subphylum Mortierellomycotina. The widespread genus contains about 85 species.

Pythium ultimum is a plant pathogen. It causes damping off and root rot diseases of hundreds of diverse plant hosts including corn, soybean, potato, wheat, fir, and many ornamental species. P. ultimum belongs to the peronosporalean lineage of oomycetes, along with other important plant pathogens such as Phytophthora spp. and many genera of downy mildews. P. ultimum is a frequent inhabitant of fields, freshwater ponds, and decomposing vegetation in most areas of the world. Contributing to the widespread distribution and persistence of P. ultimum is its ability to grow saprotrophically in soil and plant residue. This trait is also exhibited by most Pythium spp. but not by the related Phytophthora spp., which can only colonize living plant hosts.

<i>Mucor mucedo</i> Species of fungus

Mucor mucedo, commonly known as the common pinmould, is a fungal plant pathogen and member of the phylum Mucoromycota and the genus Mucor. Commonly found on soil, dung, water, plants and moist foods, Mucor mucedo is a saprotrophic fungus found world-wide with 85 known strains. It is often mistaken for Rhizopus rots on fruits due to similar mould growth shape and colour. Contrastingly, however, Mucor mucedo is found to grow on a wide range of stored grains and plants, including cucumber and tomato. Discovered in Italy in 1729 by P.A. Micheli and later noted by Carl Linnaeus in 1753 in the Species Plantarum, Mucor mucedo was originally classified as Mucor vulgaris by Micheli but later classified synonymous under name Mucor mucedo. The species was redescribed as Ascophora mucedo by H.J. Tode in 1790 but this type resided in a stoloniferous habitat and was later made the type of new genus Rhizopus.

<i>Mucor racemosus</i> Species of fungus

Mucor racemosus is a rapidly growing, weedy mould belonging to the division Mucoromycota. It is one of the earliest fungi to be grown in pure culture and was first isolated in 1886. It has a worldwide distribution and colonizes many habitats such as vegetational products, soil and houses. The fungus is mostly known for its ability to exhibit both filamentous and yeast-like morphologies, often referred to as dimorphism. Stark differences are seen in both forms and conditions of the environment heavily affect the phases of the M. racemosus. Like many fungi, it also reproduces both sexually and asexually. The dimorphic capacity of this species has been proposed as an important factor in its pathogenicity and has enhanced the industrial importance. This species is considered an opportunistic pathogen, generally limited to immunocompromised individuals. It also been associated with allergy and inflammations of facial sinuses. Its association with allergy has made it a common fungus used in allergen medical testing. Industrial use of the fungus is in the production of enzymes and the manufacture of certain dairy foods.

<span class="mw-page-title-main">Mucormycosis</span> Fungal infection

Mucormycosis, also known as black fungus, is a serious fungal infection that comes under fulminant fungal sinusitis, usually in people who are immunocompromised. It is curable only when diagnosed early. Symptoms depend on where in the body the infection occurs. It most commonly infects the nose, sinuses, eyes and brain resulting in a runny nose, one-sided facial swelling and pain, headache, fever, blurred vision, bulging or displacement of the eye (proptosis), and tissue death. Other forms of disease may infect the lungs, stomach and intestines, and skin.

<span class="mw-page-title-main">Fungus</span> Biological kingdom, separate from plants and animals

A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as one of the traditional eukaryotic kingdoms, along with Animalia, Plantae and either Protista or Protozoa and Chromista.

<i>Conidiobolus coronatus</i> Species of fungus

Conidiobolus coronatus is a saprotrophic fungus, first described by Costantin in 1897 as Boudierella coronata. Though this fungus has also been known by the name Entomophthora coronata, the correct name is Conidiobolus coronatus. C. coronatus is able to infect humans and animals, and the first human infection with C. coronatus was reported in Jamaica in 1965.

<span class="mw-page-title-main">Mortierellaceae</span> Family of fungi

The Mortierellaceae are a family of fungi in the order Mortierellales. The family contains six genera and 93 species.

<i>Spinellus fusiger</i> Species of fungus

Spinellus fusiger, commonly known as bonnet mold, is a species of fungus in the phylum Zygomycota. It is a pin mold that is characterized by erect sporangiophores that are simple in structure, brown or yellowish-brown in color, and with branched aerial filaments that bear the zygospores. It grows as a parasitic mold on mushrooms, including several species from the genera Mycena, including M. haematopus, M. pura, M. epipterygia, M. leptocephala, and various Collybia species, such as C. alkalivirens, C. luteifolia, C. dryophila, and C. butyracea. It has also been found growing on agaric species in Amanita, Gymnopus, and Hygrophorus.

<i>Apophysomyces variabilis</i> Species of fungus

Apophysomyces variabilis is an emerging fungal pathogen that can cause serious and sometimes fatal infection in humans. This fungus is a soil-dwelling saprobe with tropical to subtropical distribution. It is a zygomycete that causes mucormycosis, an infection in humans brought about by fungi in the order Mucorales. Infectious cases have been reported globally in locations including the Americas, Southeast Asia, India, and Australia. Apophysomyces variabilis infections are not transmissible from person to person.

<i>Mucor plumbeus</i> Species of fungus

Mucor plumbeus is a fungus in the family Mucoraceae that is very common, abundant and distributed worldwide. Mucor plumbeus is not known to be a plant or animal pathogen; however it is able to elicit an immune response in humans by activating the complement system. This species is commonly found in various types of soils over a range of pH, although alkaline soils seem more conducive to its growth. It is also known from the roots of wheat, oat and barley. In addition, M. plumbeus is a common fungal contaminant of indoor built environments. This species shares many similarities with M. racemosus, another fungus that belongs to the family Mucoraceae which is known to cause mucormycosis. Mucor plumbeus is a common spoilage agent of cheese, apples, apple cider and yogurt.

<i>Cunninghamella echinulata</i> Species of fungus

Cunninghamella echinulata is a fungal species in the genus Cunninghamella. It is an asexually reproducing fungus and a mesophile, preferring intermediate temperature ranges. C. echinulata is a common air contaminant, and is currently of interest to the biotechnology industry due to its ability to synthesize γ-linolenic acid as well as its capacity to bioconcentrate metals. This species is a soil saprotroph that forms rhizoids, preferring soils enriched in nitrogen, phosphorus and potassium. It has been reported occasionally an agent of mucormycosis following the inhalation of fungal spores. Czapek's agar is a suitable growth medium for the propagation of C. echinulata.

<i>Mucor circinelloides</i> Species of fungus

Mucor circinelloides is a dimorphic fungus belonging to the Order Mucorales. It has a worldwide distribution, found mostly in soil, dung and root vegetables. This species is described as not known to be able to produce mycotoxins, however it has been frequently reported to infect animals such as cattle and swine, as well as fowl, platypus and occasionally humans. Ketoacidotic patients are particularly at risk for infection by M. circinelloides.

Cladosporium herbarum is a common fungus found worldwide in organic and inorganic matter. It is efficiently distributed in the air, where it exists as the most frequently occurring fungal species. It can grow over a wide range of temperatures including very cold environments, giving it the ability to grow on refrigerated meat and form "black spots". Its high prevalence in the air and production of allergens makes C. herbarum an important exacerbant of asthma and hay fever.

<i>Mortierella polycephala</i> Species of fungus

Mortierella polycephala is a saprotrophic fungus with a wide geographical distribution occurring in many different habitats from soil and plants to salt marshes and slate slopes. It is the type species of the genus Mortierella, and was first described in 1863 by Henri Coemans. A characteristic feature of the fungus is the presence of stylospores, which are aerial, spiny resting spores (chlamydospores).

<i>Backusella</i> Genus of fungi

Backusella is the sole genus of zygote fungi in the family Backusellaceae, which is classified in the order Mucorales. Members of this genus have been often isolated from plant litter, from locations around the world.

<span class="mw-page-title-main">Mucoromycota</span> Diverse group of molds

Mucoromycota is a division within the kingdom fungi. It includes a diverse group of various molds, including the common bread molds Mucor and Rhizopus. It is a sister phylum to Dikarya.

References

Creative Commons by small.svg  This article incorporates text by James Coopman available under the CC BY 3.0 license.

  1. ↑ The genome portal of the Department of Energy Joint Genome Institute: 2014 updates. Nordberg H, Cantor M, Dusheyko S, Hua S, Poliakov A, Shabalov I, Smirnova T, Grigoriev IV, Dubchak I. Nucleic Acids Res. 2014,42(1):D26-31.
  2. ↑ Evans, Elizabeth Howell. "Studies on Mortierella ramanniana: I. Relationship between morphology and cultural behaviour of certain isolates." Transactions of the British Mycological Society 56.2 (1971): 201-IN13.
  3. ↑ Meyer, Wieland, and Walter Gams. "Delimitation of Umbelopsis (Mucorales, Umbelopsidaceae fam. nov.) based on ITS sequence and RFLP data." Mycological research 107.03 (2003): 339-350
  4. ↑ Hoff, J. A., et al. "Fungal endophytes in woody roots of Douglas‐fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa)." Forest Pathology 34.4 (2004): 255-271.
  5. ↑ Fisk, Melany C., et al. "Rhizosphere disturbance influences fungal colonization and community development on dead fine roots." Plant and soil 341.1-2 (2011): 279-293.
  6. ↑ Renker, C., et al. "Oribatid mites as potential vectors for soil microfungi: study of mite-associated fungal species." Microbial ecology 50.4 (2005): 518-528.
  7. ↑ Lardizabal, Kathryn, et al. "Expression of Umbelopsis ramanniana DGAT2A in seed increases oil in soybean." Plant physiology 148.1 (2008): 89-96.
  8. ↑ Oakes, Janette, et al. "Expression of fungal diacylglycerol acyltransferase2 genes to increase kernel oil in maize." Plant physiology 155.3 (2011): 1146-1157.
  9. ↑ Tokumasu, S., M. Sugiyama, and K. Tubaki. "Taxonomy of Mortierella ramanniana and related species." 4th international mycological congress (IMC 4), Regensburg, August. 1990.
  10. ↑ Ogawa, Yoshio, et al. "Intraspecific groups of Umbelopsis ramanniana inferred from nucleotide sequences of nuclear rDNA internal transcribed spacer regions and sporangiospore morphology." Mycoscience 46.6 (2005): 343-351.
  11. ↑ Meyer, Wieland, and Walter Gams. "Delimitation of Umbelopsis (Mucorales, Umbelopsidaceae fam. nov.) based on ITS sequence and RFLP data." Mycological research 107.03 (2003): 339-350.
  12. ↑ Ogawa, Yoshio, et al. "Polyphyly of intraspecific groups of Umbelopsis ramanniana and their genetic and morphological variation." Mycoscience 52.2 (2011): 91-98.
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