A mycoparasite is an organism with the ability to parasitize

fungi A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...

. Mycoparasites might be biotrophic or necrotrophic, depending on the type of interaction with their host.

Types of mycoparasitic organisms

Myco-heterotrophy

Various

plants Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

may be considered mycoparasites, in that they parasitize and acquire most of their nutrition from fungi during a part or all of their life cycle. These include many

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

seedlings, as well as some plants that lack chlorophyll such as ''

Monotropa uniflora ''Monotropa uniflora'', also known as ghost plant, ghost pipe, or Indian pipe, is an herbaceous perennial plant native to temperate regions of Asia, North America, and northern South America, but with large gaps between areas. The plant is some ...

''. Mycoparasitic plants are more precisely described as

myco-heterotrophs Myco-heterotrophy (from Greek μύκης , "fungus", ἕτερος ', "another", "different" and τροφή ', "nutrition") is a symbiotic relationship between certain kinds of plants and fungi, in which the plant gets all or part of its food ...

Mycoparasitic bacteria

Some

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

live on or within fungal cells as parasites or symbionts.

Mycoparasitic viruses

Some

viruses A virus is a submicroscopic infectious agent that replicates only inside the living cells Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room ...

, called

mycovirus Mycoviruses (Ancient Greek: μύκης ' ("fungus") + Latin '), also known as mycophages, are viruses that infect fungi. The majority of mycoviruses have double-stranded RNA (dsRNA) genomes and isometric particles, but approximately 30% have pos ...

es live on or within fungal cells as parasites or symbionts.

Mycoparasitic fungi

Many mycoparasites are

, though not all fungicolous fungi are

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

(some are commensals or saprobes.) Biotrophic mycoparasites acquire nutrients from living host cells. Necrotrophic mycoparasites rely on dead host cells, which they might first kill with toxins or enzymes ( saprophytic growth).

Kinds of mycoparasitic interactions

Biotrophic and necrotrophic mycoparasites

Biotrophic mycoparasites get nutrients from living host cells and growth of these parasites is greatly influenced by the metabolism of the host. Biotrophic mycoparasites tend to show high host specificity, and often form specialized infection structures. Necrotrophic mycoparasites can be aggressively antagonistic, invading the host fungus and killing, then digesting components of its cells. Necrotrophic parasites tend to have low host specificity, and are relatively unspecialized in their mechanism of parasitism.

Balanced and destructive mycoparasites

Balanced mycoparasites have little or no destructive effect on the host, whereas destructive mycoparasites have the opposite effect. Biotrophic mycoparasites are generally considered to be balanced mycoparasites; necrotrophic mycoparasites use toxins or

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

s to kill host cells, therefore necrotrophic mycoparasites are usually considered to be destructive mycoparasites. However, in some combinations, the parasite may live during its early development as a biotroph, then kill its host and act more like destructive mycoparasites in late stages of parasitization.

Mechanisms of Mycoparasitism

The four main steps of mycoparasitism include target location; recognition; contact and penetration; and nutrient acquisition.

Target location

Many research indicate that

hypha 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 o ...

l growth direction,

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

germination, and bud tube elongation of mycoparasitic fungi may exhibit

tropism A tropism is a biological phenomenon, indicating growth or turning movement of a biological organism, usually a plant, in response to an environmental stimulus. In tropisms, this response is dependent on the direction of the stimulus (as oppos ...

in response to detection of a potential host. This tropic recognition reaction is thought to arise from detection of signature chemicals of the host; the direction of the concentration gradient determines the growth direction of the parasite. As the mycoparasitic interaction is host-specific and not merely a contact response, it is likely that signals from the host fungus are recognized by mycoparasites such as ''

Trichoderma ''Trichoderma'' is a genus of fungi in the family Hypocreaceae that is present in all soils, where they are the most prevalent culturable fungi. Many species in this genus can be characterized as opportunistic avirulent plant symbionts. This ...

'' and provoke transcription of mycoparasitism-related genes.

Recognition

When mycoparasites contact their fungal host, they will recognize each other. This recognition between mycoparasites and their host fungi may be related to the

agglutinin An agglutinin is a substance in the blood that causes particles to coagulate and aggregate; that is, to change from fluid-like state to a thickened-mass (solid) state. Agglutinins can be antibodies that cause antigens In immunology, an anti ...

on the cell surface of the mycohost. Carbohydrate residues on the cell wall of mycoparasites might bind to

lectin Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in rec ...

s on the surface of the host fungi to achieve mutual recognition.

Contact and penetration

Once a mycoparasitic fungus and its host recognize each other, both may exhibit changes in external form and internal structure. Different mycoparasitic fungi form different structures when interacting with their hosts. For example, the

e of some mycoparasitic fungi form specialized contact cells resembling

haustoria In botany and mycology, a haustorium (plural haustoria) is a rootlike structure that grows into or around another structure to absorb water or nutrients. For example, in mistletoe or members of the broomrape family, the structure penetrates th ...

on the hyphae of their hosts; others may coil around the hyphae of their host fungus or penetrate then grow inside host hyphae. Nectrophic mycoparasites may kill host hyphae with toxins or enzymes before invading them.

Application

Mycoparasitic fungi can be important controls of plant disease fungi in natural systems and in agriculture, and may play a role in

integrated pest management Integrated pest management (IPM), also known as integrated pest control (IPC) is a broad-based approach that integrates both chemical and non-chemical practices for economic control of pests. IPM aims to suppress pest populations below the eco ...

(IPM) as biological controls Some ''

'' species have been developed as biocontrols of a range of commercially important diseases, and have been applied in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

India India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...

, Sweden, and other countries to control plant diseases caused by ''

Rhizoctonia solani ''Rhizoctonia solani'' is a species of fungus in the order Cantharellales. Basidiocarps (fruit bodies) are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name ''R ...

'', ''

Botrytis cinerea ''Botrytis cinerea'' is a necrotrophic fungus that affects many plant species, although its most notable hosts may be wine grapes. In viticulture, it is commonly known as "botrytis bunch rot"; in horticulture, it is usually called "grey mould" ...

'', ''

Sclerotium rolfsii ''Athelia rolfsii'' is a corticioid fungus in the family Atheliaceae. It is a facultative plant pathogen and is the causal agent of "southern blight" disease in crops. Taxonomy The species was first described in 1911 by Italian mycologist Pier ...

'', '' Sclerotinia sclerotiorum'', ''

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 fre ...

'' spp., and ''

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 ...

'' spp. as a promising alternative to chemical pesticides. Further study of mycoparasitism may drive discovery off more bioactive compounds including

biopesticide A Biopesticide is a biological substance or organism that damages, kills, or repels organisms seens as pests. Biological pest management intervention involves predatory, parasitic, or chemical relationships. They are obtained from organisms inclu ...

s and

biofertilizer A biofertilizer is a substance which contains living micro-organisms which, when applied to seeds, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of prim ...

s. {, class="wikitable" , +List of fungal bioagents with their trade and manufacturers name !Commercial products !Bioagents used !Name of the manufacturer , - , AQ10 biofungicide , '' Ampelomyces quisqualis'' isolate M-10 , Ecogen, Inc. Israel , - , Anti-Fungus , ''

'' spp. , Grondortsmettingen De Cuester, Belgium , - , Biofungus , ''Trichoderma'' spp. , Grondortsmettingen De Cuester n. V.Belgium , - , Bas-derma , '' Trichoderma viride'' , Basarass Biocontrol Res. Lab., India , - , Binab T , '' Trichoderma harzianum'' (ATCC 20476) and '' Trichoderma polysporum'' (ATCC 20475) , Bio-Innovation AB, UK , - , Bioderma , ''Trichoderma viride/T. harzianum'' , Biotech International Ltd., India , - , Biofox C , ''

Fusarium oxysporum ''Fusarium oxysporum'' (Schlecht as emended by Snyder and Hansen), an ascomycete fungus, comprises all the species, varieties and forms recognized by Wollenweber and Reinking within an infrageneric grouping called section Elegans. It is part of ...

'' (Non- pathogenic) , S. I. A. P. A., Italy , - , Prestop, Prirnastop , '' Gliocladium catenulatum'' , Kemira Agro. Oy, Finland , - , Root Pro, Root Prota to Soilgard , ''Trichoderma harzianum/ Gliocladium virens'' strain GL-21 , Efal Agr, Israel Thermo Trilogy, USA , - , Root shield, Plant shield, T-22 Planter box , ''Trichoderma harzianum'' Rifai strain KRL-AG (T-22) , Bioworks Inc., USA , - , Supresivit , ''Trichoderma harzianum'' , Borregaard and Reitzel, Czech Republic , - , T-22 G, T-22 HB , ''Trichoderma harzianum'' strain KRL-AG2 , THT Inc., USA , - , Trichodex, Trichopel , ''Trichoderma harzianum'' , Makhteshim Chemical Works Ltd., USA , - , Trichopel, Trichoject, Trichodowels, Trichoseal , ''Trichoderma harzianum'' and ''Trichoderma viride'' , Agrimm Technologies Ltd., New Zealand , - , Trichopel , ''Trichoderma harzianum''and ''Trichoderma viride'' , Agrimm Technologies Ltd., New Zealand , - , Trichoderma 2000 , ''Trichoderma'' sp. , Myocontrol Ltd., Israel , - , Tri-control , ''Trichoderma'' spp. , Jeypee Biotechs, India , - , Trieco , ''Trichoderma viride'' , Ecosense Labs Pvt. Ltd., Mumbai, India , - , TY , ''Trichoderma'' sp. , Mycocontrol, Israel

References

Parasites of fungi