Degradation of plant pathogenic fungi by <i>Trichoderma harzianum</i>

Elad, Y.; Chet, I.; Henis, Y.

doi:10.1139/m82-110

Cited by 441 publications

(218 citation statements)

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“…Extracellular secretion of variable enzymes profiles between biocontrol strains of T. harzianum have been observed in response to polysaccharides and host cell walls (Elad et al 1982, Mach et al 1999. This study found interspecies variation in expression of three mycoparasitismrelated genes.…”

Section: Discussionmentioning

confidence: 99%

Co-expression of two genes, a chitinase (chit42) and proteinase (prb1), implicated in mycoparasitism byTrichoderma hamatum

Steyaert

Stewart

Jaspers³

et al. 2004

Mycologia

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Mycoparasitism of fungal plant pathogens by Trichoderma species is a complex process that involves the production and co-ordinated secretion of cell-wall degrading enzymes. Genes implicated in mycoparasitism by Trichoderma atroviride contain motifs in the promoter region, designated MYRE1-MYRE4, that are proposed to act as binding sites for a global inducer of the mycoparasitic response. The aim of our study was to establish whether these motifs also were present in Trichoderma hamatum and whether the presence of these motifs could predict co-expression when T. hamatum was confronted by a pathogen. Using a combination of targeted, degenerate and inverse PCR, homologues of the mycoparasitismrelated genes ech42 (chit42), prb1 and lam1.3 (xbg1.3-110), which encode an endochitinase, proteinase, and ␤-1,3-glucanase, respectively, were cloned and sequenced from T. hamatum. Alignment of the promoter regions of the three genes revealed identical regions in the chit42 and prb1 promoters, which were 6-9 base pairs in length and conserved in position. Specifically, the regulator y motifs MYRE1-MYRE4 were fully conserved, together with a fifth motif, identified by this research. A substrate assay designed to investigate the response of these genes from T. harzianum and T. hamatum to a simple carbon source (glycerol) showed that, in contrast to chit42 and prb1, xbg1.3-110 was not expressed. Further comparison of the expression patterns of these three genes between T. harzianum and T. hamatum using the glycerol substrate assay showed that no Accepted for publication May 27, 2004. 1 Corresponding author. E-mail: steyaej1@lincoln.ac.nz chit42 or prb1 expression could be detected in T. harzianum when it was grown under the same conditions as T. hamatum. This showed that the response of these genes to glycerol was species specific and that a single expression pattern for these genes was not common to all Trichoderma species. Confrontation assays were used to investigate the response of the three T. hamatum genes to the more complex substrate posed by the fungal pathogen Sclerotinia sclerotiorum. Once again gene expression analysis showed that both chit42 and prb1 were co-expressed and moderately induced during confrontation against Sclerotinia sclerotiorum. Although xbg1.3-110 previously had been implicated in mycoparasitism by T. harzianum, this study detected no xbg1.3-110 expression during confrontation between T. hamatum and S. sclerotiorum. These findings show that the MYRE1-MYRE4 together with MYRE5 are present in two species of Trichoderma, T. atroviride and T. hamatum and that the presence of these motifs could predict coexpression in response to two carbon sources.

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Section: Discussionmentioning

confidence: 99%

Co-expression of two genes, a chitinase (chit42) and proteinase (prb1), implicated in mycoparasitism byTrichoderma hamatum

Steyaert

Stewart

Jaspers³

et al. 2004

Mycologia

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“…Samples were brought to laboratory and stored at 4°C until used. Five-fold serial dilutions of each soil samples were prepared in sterilized distilled water and 0.5 ml diluted sample was poured on the surface of Trichoderma Specific Medium (TSM) [8]. Plates were incubated at 28 ± 2°C for 96 h. Morphologically different colonies appearing on the plates were purified in the Potato Dextrose Agar (PDA) (HiMedia, India).…”

Section: Soil Samples and Isolationmentioning

confidence: 99%

Isolation and Characterization of Trichoderma spp. for Antagonistic Activity Against Root Rot and Foliar Pathogens

et al. 2011

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Trichoderma, soil-borne filamentous fungi, are capable of parasitising several plant pathogenic fungi. Twelve isolates of Trichoderma spp. isolated from different locations of South Andaman were characterized for their cultural, morphological and antagonistic activity against soil borne and foliar borne pathogens. The sequencing of these isolates showed seven different species. The isolates revealed differential reaction patterns against the test pathogens viz., Sclerotium rolfsii, Colletotrichum gloeosporioides and C. capsici. However, the isolates, TND1, TWN1, TWC1, TGD1 and TSD1 were most effective in percentage inhibition of mycelial growth of test pathogens. Significant chitinase and b-1,3-glucanase activities of all Trichoderma isolates has been recorded in growth medium. T. viride was found with highest chitinase whereas T. harzianum was recorded with highest b-1,3-glucanase activities.

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“…Thèse fungi produce extracellular cell-wall degrading enzymes, including chitinases, cellulases, /3-1,3-glucanases and proteases. The mycolytic activity of thèse enzymes has long been recognized as a major factor in the hyperparasitic mechanism exerted by Trichoderma (Elad et al, 1982). Différent stratégies hâve been tried to increase the chitinase activity of one of the most potent biocontrol species, T. harzianum.…”

Section: Aims and Methods Of Strain Improvementmentioning

confidence: 99%