The expression of genes involved in parasitism by Trichoderma  harzianum is triggered by a diffusible factor

Cortés, Carlos Lastanao; Gutiérrez, Ana; Olmedo, V.; Inbar, Jacob; Chet, I.; Herrera-Estrella, Alfredo

doi:10.1007/s004380050889

Cited by 126 publications

(106 citation statements)

References 31 publications

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“…Mycoparasitism by T. asperellum SKT-1 may be due to degradation of the cell wall by glycosidases, such as chitinase and b-1,3-glucanase. [35][36][37][38][39][40][41][42] The activity of cell wall-degrading enzymes is likely to be influenced by ambient temperatures, which affect both relative growth rates of fungi and enzymatic activity. 33) It is noteworthy that the optimum growth temperature (27°-30°C) of SKT-1 is almost the same as the optimum temperature for rice seed germination and seedling growth, suggesting that SKT-1 is an ideal biocontrol agent.…”

Section: Discussionmentioning

confidence: 99%

Mode of action of Trichoderma asperellum SKT-1, a biocontrol agent against Gibberella fujikuroi

et al. 2007

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Trichoderma asperellum SKT-1 and Gibberella fujikuroi, known as causal agents of "Bakanae" disease, were both transformed with genes encoding green fluorescent protein (GFP) and hygromycin B (hygB) by restriction enzyme-mediated integration (REMI). Rice seeds inoculated with GFP-tagged G. fujikuroi showed "Bakanae" symptoms. GFP-tagged SKT-1 maintained biocontrol activity against the pathogen by soaking seeds in SKT-1 spore suspension. Then, we monitored in situ interactions between SKT-1 and G. fujikuroi on rice seeds using GFP-tagged transformations under confocal scanning laser stereomicroscopy. G. fujikuroi disappeared from the embryo of rice seeds after treatment with SKT-1, whereas SKT-1 was observed on the embryo 24 hr after initiation of germination. In addition, the hyphae of G. fujikuroi were penetrated by the hyphae of SKT-1, and degradation of the cell walls of G. fujikuroi was observed under SEM in co-culture. The cell wall of G. fujikuroi on the embryo of rice seeds was lysed, suggesting that mycoparasitism is the mode of action of T. asperellum SKT-1.

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Section: Discussionmentioning

confidence: 99%

Mode of action of Trichoderma asperellum SKT-1, a biocontrol agent against Gibberella fujikuroi

et al. 2007

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“…Spores (1 ϫ 10 6 spores per ml) of the wild-type and ⌬tvk1 mutants (⌬tvk24 and ⌬tvk133) were inoculated into Potato Dextrose Broth (Difco), Vogel's medium (VMS), or minimal medium (MM) (15) and incubated for 72 h at 28°C. Then samples were analyzed by using a light microscope (BX60, Olympus, Melville, NY).…”

Section: Methodsmentioning

confidence: 99%

Enhanced biocontrol activity of Trichoderma through inactivation of a mitogen-activated protein kinase

Mendoza‐Mendoza¹,

Pozo²,

Grzegorski³

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

128

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The production of lytic enzymes in Trichoderma is considered determinant in its parasitic response against fungal species. A mitogen-activated protein kinase encoding gene, tvk1, from Trichoderma virens was cloned, and its role during the mycoparasitism, conidiation, and biocontrol was examined in tvk1 null mutants. These mutants showed a clear increase in the level of the expression of mycoparasitism-related genes under simulated mycoparasitism and during direct confrontation with the plant pathogen Rhizoctonia solani. The null mutants displayed an increased protein secretion phenotype as measured by the production of lytic enzymes in culture supernatant compared to the wild type. Consistently, biocontrol assays demonstrated that the null mutants were considerably more effective in disease control than the wild-type strain or a chemical fungicide. In addition, tvk1 gene disruptant strains sporulated abundantly in submerged cultures, a condition that is not conducive to sporulation in the wild type. These data suggest that Tvk1 acts as a negative modulator during host sensing and sporulation in T. virens.

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“…A 100 mL flask containing 25 mL of half-strength potato-dextrose both (PDB) and 2.5 ϫ 10 8 conidia was incubated 14 h at 22 C in the dark on a rotary shaker (200 rpm (Lorito et al 1996), STRE (CCCCT) is a stress-response motif (Cortés et al 1998), AbaA and BrlA (5ЈCATTCY3Ј, 5ЈMRAGGGR3Ј) bind to regulators of light-induced sporulation (Andrianopoulos and Timberlake 1994, Chang and Timberlake 1992), AceI and AceII (5ЈAGGCA3Ј, 5ЈGGCTAA3Ј) are involved in induction of cellobiohydrolase genes in reponse to cellulose (Saloheimo et al 2000, Aro et al 2001, GATA (5ЈHGATAR3Ј) binds to a regulator of nitrogen repression (Olmedo-Monfil et al 2002), PacC (5ЈGCCARG3Ј) binds to the ambient pH regulator PacC (Denison2000). MYRE4-MYRE1 are postulated to be involved in mycoparasitism and were identified previously (Cortés et al 1998). CP (chit42 and prb1), and PX (prb1 and xbg1.3-110) motifs were identified in this study: CP-1 (5ЈATTAGAGCT3Ј), CP-2 (5ЈAACGTT3Ј), CP-3 (5ЈTTCTAG3Ј), CP-4 (5ЈTTGACT3Ј), CX-1 (5ЈGGAGAC3Ј), CX-2 (5ЈTGGGTT3Ј), CX-3 (5ЈTCCTGC3Ј), PX-1 (5ЈGAAATCG3Ј), PX-2 (5ЈATTTAAG3Ј).…”

Section: Methodsmentioning

confidence: 99%

“…The endochitinase gene ech42 and alkaline proteinase gene prb1 have been characterized extensively from T. atroviride (Lorito et al 1996, Cortés et al 1998 [isolate previously referred to as T. harzianum, later reclassified as T. atroviride {Kullnig et al 2001}]), revealing many insights into the regulation of these genes. Carbon catabolite repression through binding of Cre1 to the promoter (Lorito et al 1996) is considered the major negative regulator of the mycoparasitic response.…”

Section: Introductionmentioning

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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The expression of genes involved in parasitism by Trichoderma harzianum is triggered by a diffusible factor

Cited by 126 publications

References 31 publications

Mode of action of Trichoderma asperellum SKT-1, a biocontrol agent against Gibberella fujikuroi

Mode of action of Trichoderma asperellum SKT-1, a biocontrol agent against Gibberella fujikuroi

Enhanced biocontrol activity of Trichoderma through inactivation of a mitogen-activated protein kinase

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

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