| Mortierella | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Mucoromycota |
| Order: | Mortierellales |
| Family: | Mortierellaceae |
| Genus: | Mortierella Coem. (1863) |
| Type species | |
| Mortierella polycephala Coem. (1863) | |
| Species | |
| Synonyms [1] | |
ActinomortierellaChalab. (1968) Contents | |
Mortierella species are soil fungi belonging to the order Mortierellales within the subphylum Mortierellomycotina (phylum: Mucoromycota). [2] The widespread genus contains about 85 species. [3]
The genus name of Mortierella is in honour of the Belgian Barthélemy Dumortier (1797–1878), a botanist and Member of Parliament. [4]
The genus was circumscribed by Henri Eugène Lucien Gaëtan Coemans in Bull. Acad. Roy. Sci. Belgique series 2, Vol.15 on pages 536–539 in 1863.
Species of Mortierella live as saprotrophs in soil, on decaying leaves and other organic material. Other species live on fecal pellets or on exoskeletons of arthropods. [5] [6] Penicillium, Trichoderma, Mucor and Mortierella species belong to an ecology group which are the first organisms growing on roots. Salt described that the frequency of Mortierella species growing on the surface of roots from spruce is higher in comparison to other species (e.g. Fusarium , Pythium etc.). [7]
(Distribution map on EOL)
Mortierella fungi are typically coenocytic, but compared with the genus Mucor (Mucoromycotina, Mucorales), they have a stronger tendency towards septum formation. Compared with Mucor-like fungi, the mitosporangia are typically smaller, contain fewer spores and lack a columella (Fig. 1). Many Mortierella-like fungi are asexual. However, if zygospores are found, they strongly resemble Mucor-zygospores. Sometimes sexual structures are embedded in loosely arranged hyphal networks.
Mortierella can grow on yeast extract, fish meal, or other media rich in nutrients. Most laboratories grow these fungi on potato dextrose agar or corn meal agar. The genus can also grow on PARP media, which is used as a common selective medium for Pythium. Because of its similar appearance to Pythium in culture, separation of the two can be difficult until sporulation occurs. Cultivation and growth of Mortierella fungi are affected by the carbon source, addition of minerals and nitrogen source. Monosaccharides are most frequently used for the growth. [8] Yeast extract and soybean meal are widely used as nitrogen source. [9] [10] Especially the balance between carbon and nitrogen in the medium influences the fungal culture.
Many Mortierella spp. are chitinolytic. Experiments show that they degrade chitin nearly as efficiently as chitinolytic actinomycetes. From some Mortierella species it is also known that they are able to degrade hemicelluloses to sugar by using the enzyme xylanase. This fungus can degrade the hemicellulose from plants to get sugars for their growth. [11]
Some Mortierella species show sexual developmental programs in addition to mitotic reproduction.
Mortierella forms zygospores that are the developmental consequence of plasmogamy between gametangia belonging to complementary mating types. The zygospores of Mortierella spp. may be naked (Fig 2 A) or surrounded by sterile hyphae (Fig 2 B) that form a nest-like structure, which may be interpreted as evolutionary early fruiting bodies.
Some Mortierella species are homothallic (M. epigama, M. parvispora, M. nigrescens, M. rostafinskii, M. polycephala, M.renispora), but most are heterothallic (M. elongata, M. marburgensis, M. umbelata, M. capitata, M. indohi). [12] The species Mortierella alpina was found to be homothallic and to form zygospores with a hyphal coat. Most Mortierella species have been found to be heterothallic and to produce naked zygospores with unequal suspensors. Very often sexual structures differ in size between mating types. The smaller suspensor, progametangium or gametangium does not enlarge during sexual development and may disappear soon after plasmogamy. The early development of such heterogametangic zygospores is illustrated in the heterothallic species, M. umbellata. In this species, hyphal coiling occurs at the contact site of sexually compatible mycelia. This is followed by development of progametangia which grow in parallel and close to each other. At the end of this development, one partner, the macroprogametangium will be larger than the other, the microprogametangium.
Umbelopsis isabellina, which used to be mis-classified as Mortierella isabellina, produces γ-linolenic acid, an important poly-unsaturated fatty acid. It was re-classified as belonging to the genus Umbelopsis in part based on its fatty acid profile, in addition to classical ribosomal DNA sequencing. Various poly-unsaturated fatty acids including arachidonic acid are produced by Mortierella alpina. Poly-unsaturated fatty acids contain two or more double bonds and are the acyl components of cellular lipids. Today, long-chain poly-unsaturated fatty acids are regarded as substances with beneficial potential in pharmaceutic and nutritional applications. They also serve a wide variety of purposes, from being a purely structural element in phospholipids to being involved in signal transduction, and as a substrate for a host of derivatives involved in second messenger function. [13] Many species of the genus Mortierella have been found to yield exceptionally high quantities of arachidonic acid depending on the fermentation media and culture conditions. [14] Fatty acids are normally produced in submerged culture with high carbon source supply, although this technique has drawbacks with respect to energy consumption and waste water production. In the long run, fatty acid fermentation needs to be done under economically reasonable solid-state fermentation conditions.
Mortierella species are usually non-pathogenic for plants or animals and humans. A rare example for a pathogen is Mortierella wolfii, which is until now the only pathogen of humans and other animals. Mortierella wolfii, normally isolated from soil, rotten silage and similar substrates, causes bovine abortion, pneumonia and systemic mycosis. [15]
Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defining feature of this fungal group is the "ascus", a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of Ascomycota are asexual and thus do not form asci or ascospores. Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens such as Cladonia belong to the Ascomycota.
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.
Aspergillus is a genus consisting of several hundred mold species found in various climates worldwide.
Eicosatetraenoic acid (ETA) designates any straight chain tetra-unsaturated 20-carbon fatty acid. The pure compounds, which are rarely encountered, are colorless oils. Two isomers, both of them essential fatty acids, are of particular interest:
Mucor is a microbial genus of approximately 40 species of molds in the family Mucoraceae. Species are commonly found in soil, digestive systems, plant surfaces, some cheeses like Tomme de Savoie, rotten vegetable matter and iron oxide residue in the biosorption process.
Blakeslea trispora is a mould and member of the division Zygomycota. This species has been well studied for its ability to produce carotenoids, particularly, β-carotene and lycopene. β-carotene is a vitamin A precursor and both of β-carotene and lycopene play a significant role in the inhibition of oxidative stress. Blakeslea trispora is commonly isolated from soil samples throughout the Southern United States and Southern Asia. B. trispora is a pathogen of tropical plants. In vivo pathogenicity testing using animal models suggests this fungus is not a cause of animal or human disease.
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.
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.
Homothallic refers to the possession, within a single organism, of the resources to reproduce sexually; i.e., having male and female reproductive structures on the same thallus. The opposite sexual functions are performed by different cells of a single mycelium.
The Mortierellaceae are a family of fungi in the order Mortierellales. The family contains six genera and 93 species.
Spinellus fusiger, commonly known as bonnet mold, is a species of fungus in the phylum Mucoromycota. 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.
Single cell oil, also known as Microbial oil consists of the intracellular storage lipids, triacyglycerols. It is similar to vegetable oil, another biologically produced oil. They are produced by oleaginous microorganisms, which is the term for those bacteria, molds, algae and yeast, which can accumulate 20% to 80% lipids of their biomass. The accumulation of lipids take place by the end of logarithmic phase and continues during station phase until carbon source begins to reduce with nutrition limitation.
Rhizopus oryzae is a filamentous heterothallic microfungus that occurs as a saprotroph in soil, dung, and rotting vegetation. This species is very similar to Rhizopus stolonifer, but it can be distinguished by its smaller sporangia and air-dispersed sporangiospores. It differs from R. oligosporus and R. microsporus by its larger columellae and sporangiospores. The many strains of R. oryzae produce a wide range of enzymes such as carbohydrate digesting enzymes and polymers along with a number of organic acids, ethanol and esters giving it useful properties within the food industries, bio-diesel production, and pharmaceutical industries. It is also an opportunistic pathogen of humans causing mucormycosis.
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.
Globisporangium sylvaticum is a plant pathogen, an oomycete known to cause root rot and damping off in a multitude of species. These species include apples, carrot, cherry laurel, cress, cucumber, garlic, lettuce, pea, rhododendron, and spinach. Symptoms of infection include stunting, wilt, chlorosis, and browning and eventual necrosis of roots. The pathogen can by identified by the presence of thick, microscopic, round spores within the cells of the root.
Rhizopus stolonifer is commonly known as black bread mold. It is a member of Zygomycota and considered the most important species in the genus Rhizopus. It is one of the most common fungi in the world and has a global distribution although it is most commonly found in tropical and subtropical regions. It is a common agent of decomposition of stored foods. Like other members of the genus Rhizopus, R. stolonifer grows rapidly, mostly in indoor environments.
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).
Syzygites is a monotypic genus in Zygomycota. The sole described species is Syzygites megalocarpus, which was the first fungus for which sex was reported and the main homothallic representative in the research that allowed for the classification of fungi as homothallic or heterothallic. It is also the fungus from which the term "zygospore" was coined.
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.
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. 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.
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