The genus Trichoderma is commonly found in soils and on decaying wood and vegetable matter. Strains of Trichoderma are rarely associated with diseases of living plants, although an aggressive strains of Trichoderma causes a significant disease of the commercial mushroom and soil borne pathogens. Samuels [1] provides a comprehensive review of the biology of Trichoderma, and of the technological exploitation of Trichoderma species for enzyme production and biological control. In Trichoderma species sexual reproduction is not present and are believed to be mitotic and clonal. The nomenclature of these fungi is complicated because of their pleiomorphism -that is, some of them can exist in two morphologically and physiologically different stages. The sexual (teleomorphic) stage is known by the generic name Hypocrea, whereas the asexual (anamorphic or mitosporic) stage is called Trichoderma; here, we refer to the genus collectively as Hypocrea/Trichoderma. However, despite these significant advances in our knowledge of the genus, the taxonomy of Trichoderma is still incomplete, and the distinction of species in the genus Trichoderma remains problematic. A refined classification and identification is necessary for predictive indications about ecology.
 
Taxonomic history
 
Although the genus Trichoderma has been known since 19th century. Its association with teleomorphs in Hypocrea Fr. was recognized by the Tulasne brothers in 1865, its taxonomy has remained obscure until recent decades. Bisby [2] thought that the morphological variation could be ascribed to a single species, T. viride. The first serious attempt to morphologically distinguish species, or “species aggregates”, was made by Rifai [3], who was aware that the nine taxa he distinguished were not biological entities correlated with single teleomorph species. These and a few additional species described subsequently were keyed out by Domsch et al. [4]. Teleomorph connections were established by means of ascospore isolates by Dingley [5], and by Webster and coworkers (Rifai and Webster, Webster and Rifai). In Japan, a wealth of teleomorphs was studied thoroughly and described with cultural and anamorph characters by Doi [6-7], but unfortunately no cultures have been preserved from this study. No further morphological differentiation of the anamorphs was attempted by Doi and Doi. The most detailed morphological studies of the anamorphs were carried out by Bissett [8-12], who now distinguishes about 21 taxa in sect. Pachybasium and seven in sect. Longibrachiatum, while the remaining sections have not yet been treated in a comparable way. Such studies show that the delimitation of biological species is extremely difficult in this genus on morphological grounds alone.
 
Other taxonomic methods supplementary to morphology include studies of secondary metabolites, which show a great diversity in this genus [13]. Physiological features detectable in microtiter plates may eventually provide a useful system for identification. Isoenzyme profiles have been used as an effective taxonomic tool [14]. Molecular data, particularly sequences of the ITS region of ribosomal DNA and fingerprinting techniques, have in recent years allowed the finest resolution of taxonomic entitiesn [15-17].

Citation: Srivastava M, Shahid M, Pandey S, Singh A, Kumar V, et al. (2014) Trichoderma Genome to Genomics: A Review. J Data Mining Genomics Proteomics5:162 doi: 10.4172/2153-0602.1000162

 

• Share this page
• 
• 
• 
• 
• 
•