Mycoparasitism studies of Trichoderma harzianum strains against Rhizoctonia solani: evaluation of coiling and hydrolytic enzyme production

Abstract

The genus Trichoderma is a potential biocontrol agent against several phytopathogenic fungi. One parameter for its successful use is an efficient coiling process followed by a substantial production of hydrolytic enzymes. The interaction between fifteen isolates of Trichoderma harzianum and the soil-borne plant pathogen, Rhizoctonia solani, was studied by light microscopy and transmission electron microscopy (TEM). Macroscopic observations of fungal growth in dual cultures revealed that growth inhibition of the pathogen occurred soon after contact with the antagonist. All T. harzianum isolates tested exhibited coiling around the hyphae of R. solani. The strains ALL23, ALL40, ALL41, ALL43 and ALL49 did not differ in coiling frequency and gave equal coiling performances. No correlation between coiling frequency and the production of cell wall-degrading chitinases, N-acetyl-beta-D-glucosaminidase and beta-1,3-glucanases, was found.

Biocontrol for Rhizoctonia Stem Rot Disease by Using Combination of Specific Endophyte in Paddy Tidal Swamp

“…are similar in ability according to Benhamou et al (2002) in a way that both of them could colonize the surface of plant roots quickly, protecting from any pathogenic attack. Almeida et al (2007), however, agreed that those two were known for their role in producing chitinase, β-glucanase 1-3 and 1-4 glucosidase enzymes. Thomashow and Weller (1996) added that this ability was triggered by the presence of toxins, antibiotics and siderophores.…”

Antagonism of Trichoderma spp. against Macrophomina phaseolina: Evaluation of Coiling and Cell Wall Degrading Enzymatic Activities

“…The level of reducing sugar released was determined by the DNSA method, using N-acetylglucosamine and glucose as a standard [14]. Cellulase activity (EC 3.2.1.21) was determined by measuring the amount of glucose formed from carboxy methyl cellulose [15].…”

“…The interaction between fifteen isolates of T. harzianum and the soil-borne plant pathogen, Rhizoctonia solani, was studied using light microscopy and Transmission Electron Microscopy (TEM) which showed efficient coiling process followed by a substantial production of hydrolytic enzymes [14]. Howell [1] examined Trichoderma that attaches to the pathogen with cell-wall carbohydrates that bind to pathogen lectins.…”

Cultura mista, manipulação química e genética de micro-organismos: estratégias para a diversificação do metabolismo secundário

“…Em culturas mistas, microorganismos produzem enzimas como proteases, β-1,3-glucanases e quitinases que podem ser responsáveis pela degradação das paredes celulares das hifas dos micro-organismos competidores (SÁNCHEZ et al, 2007;ALMEIDA et al, 2007;GUTHRIE;CASTLE, 2006), e atuarem como fatores indutores da produção de metabólitos secundários (SHIN et al, 1998). As enzimas fenol-oxidases tais como lacase e peroxidase também são conhecidas por estarem envolvidas em processos de degradação.…”

“…Considerando que durante a interação entre os microrganismos não somente a produção de metabólitos secundários pode ser induzida, mas também a produção de enzimas (SÁNCHEZ et al, 2007;ALMEIDA et al, 2007;GUTHRIE;CASTLE, 2006;SHIN et al, 1998), e que estas podem ser responsáveis pela formação das zonas de inibição observadas em meio semisólido, a produção de diferentes enzimas na região entre os micro-organismos foi investigada.…”