Influence of<i>Pseudomonas fluorescens</i>on Hyphal Growth and Biocontrol Activity of<i>Trichoderma harzianum</i>in the Spermosphere and Rhizosphere of Pea

Dandurand, Louise-Marie; Knudsen, G. R.

doi:10.1094/phyto-83-265

Cited by 88 publications

(41 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…3). Previous work in our laboratory demonstrated several environmental factors that influence radial growth and density of hyphae originating from alginate pellets of T. harzianum (11,18,19). However, previous experiments necessarily were conducted using steamed soil, because it was impossible to differentiate hyphae from different sources in raw soil.…”

Section: Resultsmentioning

confidence: 99%

“…Significant biotic factors may include soil bacteria (3,11,15), indigenous soil fungi, and soil microfauna (4) that can influence the growth and efficacy of the introduced fungus. These are areas for future investigation.…”

Section: Resultsmentioning

confidence: 99%

“…For example, Knudsen and coworkers (11,18) quantified the influences of temperature, soil matric potential, nutrient source, and antagonistic bacteria on the hyphal growth and biocontrol efficacy of pelletized T. harzianum in soils. However, it was not possible to differentiate the hyphal growth of this fungal agent from that of indigenous Trichoderma strains (3,18).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Cotransformation of Trichoderma harzianum with β-Glucuronidase and Green Fluorescent Protein Genes Provides a Useful Tool for Monitoring Fungal Growth and Activity in Natural Soils

Bae

Knudsen

2000

Appl Environ Microbiol

View full text Add to dashboard Cite

Trichoderma harzianum was cotransformed with genes encoding green fluorescent protein (GFP), ␤-glucuronidase (GUS), and hygromycin B (hygB) resistance, using polyethylene glycol-mediated transformation. One cotransformant (ThzID1-M3) was mitotically stable for 6 months despite successive subculturing without selection pressure. ThzID1-M3 morphology was similar to that of the wild type; however, the mycelial growth rate on agar was reduced. ThzID1-M3 was formed into calcium alginate pellets and placed onto buried glass slides in a nonsterile soil, and its ability to grow, sporulate, and colonize sclerotia of Sclerotinia sclerotiorum was compared with that of the wild-type strain. Wild-type and transformant strains both colonized sclerotia at levels above those of indigenous Trichoderma spp. in untreated controls. There were no significant differences in colonization levels between wild-type and cotransformant strains; however, the presence of the GFP and GUS marker genes permitted differentiation of introduced Trichoderma from indigenous strains. GFP activity was a useful tool for nondestructive monitoring of the hyphal growth of the transformant in a natural soil. The green color of cotransformant hyphae was clearly visible with a UV epifluorescence microscope, while indigenous fungi in the same samples were barely visible. Green-fluorescing conidiophores and conidia were observed within the first 3 days of incubation in soil, and this was followed by the formation of terminal and intercalary chlamydospores and subsequent disintegration of older hyphal segments. Addition of 5-bromo-4-chloro-3-indolyl-␤-D-glucuronic acid (X-Gluc) substrate to recovered glass slides confirmed the activity of GUS as well as GFP in soil. Our results suggest that cotransformation with GFP and GUS can provide a valuable tool for the detection and monitoring of specific strains of T. harzianum released into the soil.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Cotransformation of Trichoderma harzianum with β-Glucuronidase and Green Fluorescent Protein Genes Provides a Useful Tool for Monitoring Fungal Growth and Activity in Natural Soils

Bae

Knudsen

2000

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…Results from both methods indicated that T. harzianum ThzID1-M3 colonised all of the sclerotia that were sampled, and that colonisation was observable over the 40-d experimental period (Figs 1A and 3A). We previously observed that, in soil, the formulated fungus grows rapidly for 5e7 d after which growth slows or stops, presumably due to effects including microbial antagonists, predation (e.g., by fungivorous nematodes), and limited nutritional resources Dandurand & Knudsen 1993;Bae & Knudsen 2000;Bae & Knudsen 2001). Orr & Knudsen (2004) observed that hyphal density of T. harzianum ThzID1-M3 applied to soil peaked from 3 to 6 d after application, followed by a rapid decrease.…”

Section: Discussionmentioning

confidence: 99%

Comparison of real-time PCR and microscopy to evaluate sclerotial colonisation by a biocontrol fungus

Kim

Knudsen

2011

Fungal Biology

View full text Add to dashboard Cite

“…Strain mixtures have indeed proven in some cases to be more effective than single strain treatments against a variety of plant diseases [2][3][4][5][6][7]. There are, however, other reports of biocontrol strain combinations that had no effect on efficacy or even reduced the level of disease suppressive activity of individual antagonists [8][9][10][11][12]. An important prerequisite for designing effective strain mixtures is choosing strains that complement rather than interfere with the antagonistic activity of each antagonist.…”

Section: Introductionmentioning

confidence: 99%

Signaling between bacterial and fungal biocontrol agents in a strain mixture

LUTZ¹

2004

FEMS Microbiology Ecology

View full text Add to dashboard Cite

The use of bacterial and fungal strain mixtures is a promising way to improve efficacy of biocontrol treatments. Certain Pseudomonas and Trichoderma strains belong to the most common studied biocontrol agents. One key factor for the biocontrol efficacy of several P. fluorescens strains is the synthesis of 2,4-diacetylphloroglucinol (DAPG). Production of chitinases, such as the ECH42 endochitinase and the NAG1 N-acetyl-b-D D -glucosaminidase, is a primary mechanism of action for T. atroviride. We examined the molecular interactions between the DAPG-producing P. fluorescens strains CHA0 and Q2-87 and chitinase-producing T. atroviride P1. Interactions were monitored using the reporter gene constructs, phlA'-'lacZ translational fusion in P. fluorescens CHA0 and ech42-goxA or nag1-goxA fusions in T. atroviride P1. We found that DAPG enhanced nag1, but not ech42 expression, whereas an unidentified substance from P. fluorescens CHA0 repressed expression of both Trichoderma chitinases. Addition of T. atroviride P1 culture filtrates to growing cultures of P. fluorescens enhanced phlA expression transiently during growth. These results indicate that negative and positive effects on expression of key biocontrol genes may occur while mixing antagonists.

show abstract

Influence ofPseudomonas fluorescenson Hyphal Growth and Biocontrol Activity ofTrichoderma harzianumin the Spermosphere and Rhizosphere of Pea

Cited by 88 publications

References 0 publications

Cotransformation of Trichoderma harzianum with β-Glucuronidase and Green Fluorescent Protein Genes Provides a Useful Tool for Monitoring Fungal Growth and Activity in Natural Soils

Cotransformation of Trichoderma harzianum with β-Glucuronidase and Green Fluorescent Protein Genes Provides a Useful Tool for Monitoring Fungal Growth and Activity in Natural Soils

Comparison of real-time PCR and microscopy to evaluate sclerotial colonisation by a biocontrol fungus

Signaling between bacterial and fungal biocontrol agents in a strain mixture

Contact Info

Product

Resources

About