''Trichoderma koningii'' is a very common soil dwelling

saprotroph Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ( ...

with a worldwide distribution. It has been heavily exploited for agricultural use as an effective

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 ...

, having been frequently cited as an alternative biological control agent in the regulation of fungi-induced plant diseases. They are

endosymbiont An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "withi ...

s associated with plant root tissues, exhibiting

mycoparasitism A mycoparasite is an organism with the ability to parasitize fungi. Mycoparasites might be biotrophic or necrotrophic, depending on the type of interaction with their host. Types of mycoparasitic organisms Myco-heterotrophy Various plants may ...

and promoting plant growth due to their capacity to produce different

secondary metabolite Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the no ...

s. ''Trichoderma koningii'' is a species belonging to the genus ''

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 ...

''. Fungi in this genus are able to adapt to different

ecological niche In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (fo ...

s and can colonize their habitats effectively, allowing them to be powerful antagonists and biocontrol agents. Typical of ''Trichoderma'' species is having a fast growth rate and the production of green or

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

conidia A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to th ...

on a branched

conidiophore A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to the ...

structure.

History and taxonomy

''Trichoderma koningii'' was first described by the Dutch mycologist Oudemans in 1902 as one of the species in the microbial flora he obtained from a nature preserve in The

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

. After the genus was erected in 1794, there was difficulty in distinguishing and identifying the different species apart due to their very similar morphological characteristics. It wasn't until 1969 that a concept of classification was proposed by Rifai to reduce confusion on the taxonomy of ''Trichoderma''. He recognized ''T. koningii'' as one of the nine "aggregates" or groups of species in the genus. This aggregate consists of 12 species within three lineages that have similar morphology as the "true" ''T. koningii'' but can be differentiated from each other by their phenotypic characters and geographic distributions. In 1991, Bissett divided the genus into five sections to classify the species on the basis of the branching of conidiophores. He included ''T. koningii'' in ''Trichoderma'' sect. ''Trichoderma''. In 2004, Chaverri and Samuels proposed another taxonomic classification based on molecular phylogenetic analysis. ''T. koningii'' and its aggregates were included in the ''T. viride'' clade.

Growth and morphology

The conidiophores of ''T. koningii'' are branched and organized in a pyramidal structure with longer branches at the base that progressively shortens as it nears the tip. Primary and secondary branches arise in a right-angle degree and are often symmetrical on either side of the node along the main axis.

Phialide The phialide ( ; el, phialis, diminutive of phiale, a broad, flat vessel) is a flask-shaped projection from the vesicle (dilated part of the top of conidiophore) of certain fungi. It projects from the mycelium without increasing in length unless ...

s are usually in 3–4 whorls that arise from the tip of the main branch and from lateral branches at intercalary positions on the conidiophore. Some phialides on widely-spaced branches are flask-shaped, resembling a wine bottle, whereas some tend to have a very swollen middle when in dense clusters or "pseudo-

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral d ...

". ''T. koningii'' typically produces smooth and

ellipsoidal An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ze ...

(egg-shaped) conidia, with a mean length of 4.1–4.3 µm, that aggregates in a slimy green mass at the tip of the phialides. The

chlamydospores A chlamydospore is the thick-walled large resting spore of several kinds of fungi, including Ascomycota such as '' Candida'', Basidiomycota such as '' Panus'', and various Mortierellales species. It is the life-stage which survives in unfavourable ...

are pale brown, globe-like in shape, and are located at terminal and intercalary positions on the hyphae. In culture, colonies display rapid growth on

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

(PDA), as cream-coloured in the beginning but later turns green because of sporulation. ''T. koningii'' grows at an optimum temperature of 25 °C in darkness, producing white

mycelium 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 in ...

with a radius of 50–60 mm. During conidial production, colouration first begins at the centre then later spreads outward in dark or dull green concentric rings that are vague to noticeable. Maximum temperature for growth is observed at 33 °C, which reduces their pathogenic potential in humans. Like most ''Trichoderma'' species, this fungus has a sexual state. The

teleomorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an asex ...

, ''Hypocrea koningii'', is characterized by cushion-shaped stromata (sing. stroma) that are broadly attached to the surface of a substrate but are free at the margins. The surface of the stroma appears slightly-wrinkled. Mature stromata are brown to brownish-orange, whereas the young ones have a tan color with villi sprouting from the surface. These short hairs are lost during development.

Perithecia An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

(fruiting bodies) are

elliptic In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. It generalizes a circle, which is the special type of ellipse in ...

, 160–280 µm long and 100–185 µm wide. The perithecial neck has a length of 53–90 µm. Asci (sing.

ascus An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera o ...

) within the fruiting bodies are typically

cylindrical A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an in ...

, with dimensions of 60–70 x 4–5.7 µm and thickening at the apex. The

ascospores An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or ...

of ''H. koningii'' are hyaline and fill up the ascus in a single row. They are initially bicellular but have become separated into part-ascospores. The proximal part of the ascospore is ellipsoidal while the distal part is globe-like and longer.

Physiology

''Trichoderma koningii'' is employed as a biological control agent because of its mycoparasitic and antagonistic ability. This fungus is capable of biosynthesizing

silver nanoparticles Silver nanoparticles are nanoparticles of silver of between 1 nm and 100 nm in size. While frequently described as being 'silver' some are composed of a large percentage of silver oxide due to their large ratio of surface to bulk silve ...

volatile organic compounds Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature. High vapor pressure correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, ...

and secondary metabolites such as trichokonins, koninginins, and

pyrone Pyrones or pyranones are a class of heterocyclic chemical compounds. They contain an unsaturated six-membered ring containing one oxygen atom and a ketone functional group. There are two isomers denoted as 2-pyrone and 4-pyrone. The 2-pyrone (o ...

s. Silver nanoparticles (AgNPs) are produced via the reduction and capping of Ag⁺ to Ag⁰ by the enzymes and proteins released by ''T. koningii''. Koninginins are substances capable of inhibiting the process of inflammation. Koninginins isolated from ''T. koningii'' are identified to be A, E, F, L and M (KonA, KonE, KonF, KonL, KonM). Trichokonins are

peptaibol Peptaibols are biologically active peptides containing between seven and twenty amino acid residues, some of which are non-proteinogenic amino acids. In particular, they contain α-aminoisobutyric acid along with other unusual aminoacids such as e ...

s that exhibit antimicrobial property. Other

polyketides Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynth ...

reportedly isolated from ''T. koningii'' are Trichodermaketones A-D, 7-O-Methylkoninginin D, and 6-pentyl alpha pyrone which can inhibit the germination of other fungal spores. ''T. koningii'' is also reported to produce

calcium oxalate crystals Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula . It forms hydrates , where ''n'' varies from 1 to 3. Anhydrous and all hydrated forms are colorless or white. The monohydrate ...

, particularly

weddellite Weddellite ( Ca C2 O4·2 H2O) is a mineral form of calcium oxalate named for occurrences of millimeter-sized crystals found in bottom sediments of the Weddell Sea, off Antarctica. Occasionally, weddellite partially dehydrates to whewellite, for ...

, via

biomineralization Biomineralization, also written biomineralisation, is the process by which living organisms produce minerals, often to harden or stiffen existing tissues. Such tissues are called mineralized tissues. It is an extremely widespread phenomenon; ...

. The process occurs intracellularly and extracellularly with respect to the fungus. The intracellular process involves the

vegetative growth Vegetative phase change is the juvenile-to-adult transition in plants. This transition is distinct from the reproductive transition and is most prolonged and pronounced in woody species. Manipulating phase change may be an important avenue for p ...

of the mycelium. The extracellular activity occurs through the reaction between the calcium in the environment and

oxalic acid Oxalic acid is an organic acid with the systematic name ethanedioic acid and formula . It is the simplest dicarboxylic acid. It is a white crystalline solid that forms a colorless solution in water. Its name comes from the fact that early inve ...

secreted by the fungus, leading to the production of biomineral species.

Habitat and ecology

Typical of ''Trichoderma'', ''T. koningii'' is a good colonizer of its habitat. Saprophytic growth occurs in acidified soils and soils with high water content (i.e.

chernozem Chernozem (from rus, чернозём, p=tɕɪrnɐˈzʲɵm, r=chernozyom; "black ground"), also called black soil, is a black-colored soil containing a high percentage of humus (4% to 16%) and high percentages of phosphorus and ammonia compo ...

podzol In soil science, podzols are the typical soils of coniferous or boreal forests and also the typical soils of eucalypt forests and heathlands in southern Australia. In Western Europe, podzols develop on heathland, which is often a construct of hum ...

). It is often isolated from under pine and coniferous trees, vegetation, plantations, grasslands,

marshes A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...

swamps A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

, and

peat Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficien ...

s. ''T. koningii'' also thrives in other environments, including growing on decaying wood, in marine species, estuarine sediments, and in mines and caves. The fruiting bodies commonly grow on tree bark and stromata tend to be scattered, often solitary than in clusters. It is distributed widely in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...

, 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 ...

, and

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...

. Recent surveys have reported that some strains of ''T. koningii'' are also found to be present in

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 ...

and

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...

Applications

Agriculture

''Trichoderma koningii'' are plant symbionts that induce resistance against fungal pathogen attack and stimulate growth. It acts as a parasite to other fungi, particularly those that cause diseases to plants, by inhibiting their growth or attacking them directly. It is antagonistic to various plant pathogens such as '' Gaeumannomyces graminis'' var. ''tritici'' (''Ggt''), ''

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 ...

'', and ''

Sclerotium cepivorum ''Stromatinia cepivora'' is a fungus in the division Ascomycota. It is the teleomorph of ''Sclerotium cepivorum'', the cause of white rot in onions, garlic, and leeks. The infective sclerotia remain viable in the soil for many years and are stim ...

''. It inhibits the growth of ''Ggt'' by releasing its microbial compounds. It colonizes the

rhizosphere The rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome. Soil pores in the rhizosphere can contain many bacteria and other microor ...

s to interact with the roots of seedlings and plants, preventing ''S. rolfsii'' from

damping-off Damping off (or damping-off) is a horticultural disease or condition, caused by several different pathogens that kill or weaken seeds or seedlings before or after they germinate. It is most prevalent in wet and cool conditions. Symptoms There a ...

the seedlings before they can germinate. ''T. koningii'' antagonizes ''S. cepivorum'' by acting as a secondary colonizer of the infected plant roots and secreting enzymes that cause the degradation and

lysis Lysis ( ) is the breaking down of the membrane of a cell, often by viral, enzymic, or osmotic (that is, "lytic" ) mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a ''lysate''. In molecular bio ...

of the pathogen.

Medicine

Several studies have described the ability of ''T. koningii'' to produce enzymes that exhibit antifungal and antibacterial properties. Koninginins bear similar structural elements as

flavonoids Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

and

vitamin E Vitamin E is a group of eight fat soluble compounds that include four tocopherols and four tocotrienols. Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitami ...

. They can inhibit the process of inflammation caused by snake bites. They can block the effects of

myotoxin Myotoxins are small, basic peptides found in snake venoms (e.g. rattlesnakes) and lizard venoms (e.g. Mexican beaded lizard). This involves a non-enzymatic mechanism that leads to severe muscle necrosis. These peptides act very quickly, causing i ...

s and induction of

edema Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels tight, the area ma ...

because they can inhibit phospholipase A₂, one of the proteins found in venoms. AgNPs produced using ''T. koningii'' are recognized as alternatives to antibiotics and are tools for

gene delivery Gene delivery is the process of introducing foreign genetic material, such as DNA or RNA, into host cells. Gene delivery must reach the genome of the host cell to induce gene expression. Successful gene delivery requires the foreign gene deliver ...

and

drug delivery Drug delivery refers to approaches, formulations, manufacturing techniques, storage systems, and technologies involved in transporting a pharmaceutical compound to its target site to achieve a desired therapeutic effect. Principles related to dr ...

. They also show antagonism against

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bac ...

and

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

bacteria, respectively ''

Candida albicans ''Candida albicans'' is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is usua ...

'' and ''

Salmonella typhimurium ''Salmonella enterica'' subsp. ''enterica'' is a subspecies of ''Salmonella enterica'', the rod-shaped, flagellated, aerobic, Gram-negative bacterium. Many of the pathogenic serovars of the ''S. enterica'' species are in this subspecies, includ ...

''.

References

External links

*
Index Fungorum

USDA ARS Fungal Database
{{DEFAULTSORT:Trichoderma Koningii Fungal plant pathogens and diseases Fungal pest control agents Root vegetable diseases Trichoderma Fungi described in 1902 Fungus species