Trichoderma

Trichoderma
Trichoderma harzianum , crust ball mushrooms (Hypocreales)
Systematics
Department : Ascomycota mushrooms Subdivision : Real ascent mushrooms (Pezizomycotina) Class : Sordariomycetes Subclass : Hypocreomycetidae Family : Crustball relatives (Hypocreaceae) Genre : Trichoderma
Scientific name
Trichoderma
Persoon

Trichoderma is a large genus of the crust ball mushroom relatives from the department of the hose mushrooms . Trichoderma species are filamentous fungi that are found all over the world in soil, plants, rotting plant residues or wood. They are extremely important in the rhizosphere and interact between plants, other microorganisms and soil. Due to the competition with other microorganisms, they have recently been used more and more often as antagonists to phytopathogenic fungi. Hypocrea spp. forms the main fruit form ( teleomorph ) and is found mainly in wood. Most Trichoderma strains, however, only form the anamorphic.

Macroscopic features

In culture, the fungus forms a rapidly growing air mycelium . The mycelium is white and dense, but when ripe it can be colored green to greenish yellow by the conidia . They grow faster on Potato Dextrose Agar (PDA) than on Sabouraud Dextrose Agar .

Microscopic features

The hyphae are septate and hyaline . As spores, conidia are formed phialidically on conidiophores , in T. longibrachiatum and T. viride also chlamydospores . The conidiophores are hyaline and branched. the phialides are hyaline, bottle-shaped, swollen at the base and arranged at right angles to the conidiospores and can stand individually or in clusters. The conidia are on average 3 μm in size, unicellular, round to ellipsoid and mostly green. They are grouped in heads and the phialid tips.

Importance in biological pest control

The use of antagonistic microorganisms to control phytopathogenic fungi has been the subject of extensive research. One of the most widely studied antagonists in relation to biological pest control is the genus Trichoderma.

Systematics and taxonomy

The genus Trichoderma was first described by Christian Hendrik Persoon in 1794 . However, for a long time the species only described the secondary crop forms of the genus Hypocrea , the main crop forms . Hence there were two valid names for many species. At the congress of the International Code of Botanical Nomenclature (ICBN) in Melbourne in 2011 it was decided that since January 1, 2013 only the name of the main fruit form is valid for all mushrooms, so the valid name would actually have been Hypocrea . Due to the dominant use of the generic name Trichoderma in research , it was decided to keep the name as a noun conservandum , which is to be preserved compared to the teleomorphic genus Hypocrea . This means that all species that have both a Hypocrea and a Trichoderma name are officially listed under their Trichoderma names, and that every species, including the former Podostroma species, and also those exclusively known as Hypocrea has been transferred to the genus Trichoderma .

There are 33 known species. However, a large number of phyla are known and a new order of the species is being discussed. In addition, only the anamorphs are known for many species. Important types:

• Trichoderma harzianum
• Trichoderma koningii
• Trichoderma longibrachiatum
• Trichoderma pseudokoningii
• Trichoderma reesei
• Trichoderma viride

literature

• GE Harman, CR Howell, A. Viterbo, I. Chet, M. Lorito: Trichoderma species - Opportunistic, avirulent plant symbionts . In: Nature Reviews Microbiology . 2/2004, pp. 43-56.
• CP Kubicek, GE Harman: Trichoderma and Gliocladium. Vol. 1, Taylor and Francis, London 1998, ISBN 0-7484-0572-0 .

Web links

Commons : Trichoderma  - collection of images, videos and audio files

• Trichoderma ( Memento from April 6, 2015 in the Internet Archive ) at doctorfungus.org
• W. Gams (Ed.): Hypocrea and Trichoderma studies marking the 90th birthday of Joan M. Dingley. ( Memento of September 7, 2008 in the Internet Archive ) In: Studies in Mycology. No. 56, 2006.
• GJ Samuels, P. Chaverri, DF Farr, EB McCray: Trichoderma Online.
• Trichoderma genetically exposed as a parasite

Individual evidence

1. ^ Y. Elad: Biological control of foliar pathogens by means of Trichoderma harzianum and potential modes of action . In: Crop Protection . tape 19 , no. 8-10 , September 2000, pp. 709-714 , doi : 10.1016 / S0261-2194 (00) 00094-6 .
2. ^ Trichoderma . In: MycoBank . Mycobank, accessed March 29, 2020 .  
3. ↑ Bissett J., Gams W., Jaklitsch WM, Gary J Samuels: Accepted Trichoderma names in the year 2015. In: IMA Fungus . tape 6 , 2015, p. 263–295 , doi : 10.5598 / imafungus . 06/02/02/2015 ( researchgate.net ).
4. ↑ Barbara Robbertse, Pooja K Strope, Priscila Chaverri, Romina Gazis, Stacy Ciufo, Michael Domrachev, and Conrad L Schoch: Improving taxonomic accuracy for fungi in public sequence databases: applying 'one name one species' in well-defined genera with Trichoderma / Hypocrea as a test case . In: Database (Oxford). 2017; 2017: bax072. 2017, p. bax072 , doi : 10.1093 / database / bax072 .