Molecular Characterization and Identification of Biocontrol Isolates of Trichoderma spp

Abstract

The most common biological control agents (BCAs) of the genus Trichoderma have been reported to be strains of Trichoderma virens, T. harzianum, and T. viride. Since Trichoderma BCAs use different mechanisms of biocontrol, it is very important to explore the synergistic effects expressed by different genotypes for their practical use in agriculture. Characterization of 16 biocontrol strains, previously identified as "Trichoderma harzianum" Rifai and one biocontrol strain recognized as T. viride, was carried out using several molecular techniques. A certain degree of polymorphism was detected in hybridizations using a probe of mitochondrial DNA. Sequencing of internal transcribed spacers 1 and 2 (ITS1 and ITS2) revealed three different ITS lengths and four different sequence types. Phylogenetic analysis based on ITS1 sequences, including type strains of different species, clustered the 17 biocontrol strains into four groups: T. harzianum-T. inhamatum complex, T. longibrachiatum, T. asperellum, and T. atroviride-T. koningii complex. ITS2 sequences were also useful for locating the biocontrol strains in T. atroviride within the complex T. atroviride-T. koningii. None of the biocontrol strains studied corresponded to biotypes Th2 or Th4 of T. harzianum, which cause mushroom green mold. Correlation between different genotypes and potential biocontrol activity was studied under dual culturing of 17 BCAs in the presence of the phytopathogenic fungi Phoma betae, Rosellinia necatrix, Botrytis cinerea, and Fusarium oxysporum f. sp. dianthi in three different media.

Biological control of Rhizoctonia solani in tomatoes with Trichoderma harzianum mutants

“…The molecular characterization of several wild isolates has shown a certain degree of polymorphism and the presence of three different ITS lengths (Hermosa et al 2000) and the secondary metabolites involvement in biocontrol has been recently reviewed (Reino et al 2008). Trichoderma use different mechanisms for the control of phytopathogens which include mycoparasitism, competition for space and nutrients, secretion of antibiotics and fungal cell wall degrading enzymes (Kubicek et al 2001;Howell, 2003;Benítez et al 2004;Harman et al 2004).…”

Mycophagous growth of Collimonas bacteria in natural soils, impact on fungal biomass turnover and interactions with mycophagous Trichoderma fungi

“…and Fusarium spp.) has received much attention (Hermosa et al, 2000;Whipps, 2001;Harman, 2006). Trichoderma spp.…”

Molecular Identification Of Trichoderma Strains Collected To Develop Plant Growth-Promoting And Biocontrol Agents

“…The first step in such studies should be species identification of promising Trichoderma strains. Correct species identification is necessary due to Trichoderma similarity in morphology and complex taxonomy (Hermosa et al 2000). Especially Trichoderma strains that are potentially dangerous to cultivated mushrooms (T. aggressivum f. europaeum, T. aggressivum f. aggressivum, T. pleurotum, and T. pleuroticola) should be excluded from PGPF or BCA strain selection (Komoń-Żelazowska et al 2007).…”

“…76 M. Oskiera et al ____________________________________________________________________________________________________________________ Commercial products based on Trichoderma are available on the market and are used to protect plants or to stimulate plant growth. These products are based on strains belonging to the following species: T. asperellum (T-203), T. atroviride (SC1, P1, or IMI206040), T. harzianum (NF-9, T1, T22, or 2413), and T. virens (G-6, G-6-5, or G-11) (Hermosa et al 2000;Kullnig et al 2001;Dodd et al 2003;Longa et al 2009;Chaverri et al 2015). However, since the application of beneficial microbes has become an integrated component of plant management in agricultural or horticultural practice, interest in developing new products based on Trichoderma is growing.…”