''Mortierella'' species are soil

fungi A fungus ( : fungi or funguses) 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 a kingdom, separately from ...

belonging to the order Mortierellales within the subphylum Mortierellomycotina (phylum: Mucoromycota). The widespread genus contains about 85 species.

Taxonomy

The genus name of ''Mortierella'' is in honour of Barthélemy Dumortier (1797–1878), who was a Belgian who conducted a parallel career of botanist and

Member of Parliament A member of parliament (MP) is the representative in parliament of the people who live in their electoral district. In many countries with bicameral parliaments, this term refers only to members of the lower house since upper house members o ...

. The genus was

circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every polyg ...

by Henri Eugène Lucien Gaëtan Coemans in Bull. Acad. Roy. Sci. Belgique series 2, Vol.15 on pages 536-539 in 1863.

Ecology

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 ''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 ''Fusarium'' is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil mi ...

'', ''

Pythium ''Pythium'' is a genus of parasitic oomycetes. They were formerly classified as fungi. Most species are plant parasites, but ''Pythium insidiosum'' is an important pathogen of animals, causing pythiosis. The feet of the fungus gnat are frequen ...

'' etc.).

Distribution map on EOL

Morphology

''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.

Metabolism

''Mortierella'' can grow on

yeast extract Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture media. They are often used to create savory flavors and umami taste sensations, ...

, fish meal, or other media; rich in nutrients. Most laboratories grow these fungi on

potato dextrose agar Potato dextrose agar (BAM Media M127
from the U.S.

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 Monosaccharides (from Greek '' monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units ( monomers) from which all carbohydrates are built. They are usually colorless, water ...

are most frequently used for the growth. Yeast extract and

soybean meal Soybean meal is used in food and animal feeds, principally as a protein supplement, but also as a source of metabolizable energy. Typically 1 bushel (i.e. 60 lbs. or 27.2 kg) of soybeans yields 48 lbs. (21.8 kg) of soybean meal. Some ...

are widely used as nitrogen source. 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 The Actinomycetales is an order of Actinomycetota. A member of the order is often called an actinomycete. Actinomycetales are generally gram-positive and anaerobic and have mycelia in a filamentous and branching growth pattern. Some actinomycete ...

. From some ''Mortierella'' species it is also known that they are able to degrade hemicelluloses to sugar by using the

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

xylanase. This fungus can degrade the hemicellulose from plants to get sugars for their growth.

Sexual and asexual development

Some ''Mortierella'' species show sexual developmental programs in addition to

mitotic In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...

reproduction. ''Mortierella'' forms zygospores that are the developmental consequence of

plasmogamy Plasmogamy is a stage in the sexual reproduction of fungi, in which the protoplasm of two parent cells (usually from the mycelia) fuse without the fusion of nuclei, effectively bringing two haploid nuclei close together in the same cell. This sta ...

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 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 si ...

(''M. epigama'', ''M. parvispora'', ''M. nigrescens'', ''M. rostafinskii'', ''M. polycephala'', ''M.renispora''), but most are

heterothallic Heterothallic species have sexes that reside in different individuals. The term is applied particularly to distinguish heterothallic fungi, which require two compatible partners to produce sexual spores, from homothallic ones, which are capable ...

(''M. elongata'', ''M. marburgensis'', ''M. umbelata'', ''M. capitata'', ''M. indohi''). The species ''Mortierella alpina'' was found to be homothallic and to form zygospores with a

hyphal A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

coat. Most ''Mortierella'' species have been found to be

and to produce naked zygospores with unequal suspensors. Very often sexual structures differ in size between mating types. The smaller suspensor, progametangium or

gametangium A gametangium (plural: gametangia) is an organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants. In contrast to gametogenesis in animals, a gametangium is a haploid s ...

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 Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates ...

. 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.

Biotechnology

''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. 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. 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 Solid state, or solid matter, is one of the four fundamental states of matter. Solid state may also refer to: Electronics * Solid-state electronics, circuits built of solid materials * Solid state ionics, study of ionic conductors and their use ...

fermentation conditions.

Pathogenicity

''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 Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...

and systemic mycosis.

References

External links

Pictures of ''Mortierella'' sp. on iNaturalist.org

''Mortierella'' in medicine--opportunistic pathogen ''Mortierella wolfii''

Mortierella

{{Taxonbar, from=Q2301189 Zygomycota genera