Implications of rhizosphere competence of Trichoderma harzianum

1988 ◽  
Vol 34 (3) ◽  
pp. 229-234 ◽  
Author(s):  
Jaleed S. Ahmad ◽  
Ralph Baker
Keyword(s):  
Trichoderma Harzianum ◽  
Seed Treatment ◽  
Rhizosphere Soil ◽  
Pythium Ultimum ◽  
Fruit Weight ◽  
Root Segment ◽  
Wild Type ◽  
Colony Forming Units ◽  
Effective Delivery ◽  
Additional Water

Seed treatment with conidia of rhizosphere-competent mutants of Trichoderma harzianum reduced the incidence of preemergence damping-off of barley, cucumber, pea, radish, and tomato induced by Pythium ultimum. Wild-type parents of these mutants were less effective in control. When rhizosphere-competent mutants were applied to seed or when a peat-bran preparation was added to soil, the resulting plants produced significantly higher fruit weight and higher dry weights than those treated with rhizosphere-incompetent wild types and controls. Seed treatment with mutants increased the incidence of emergence and resultant plant growth was significantly (P = 0.05) better than when mutant strains were added to soil in peat–bran. There was, however, no significant (P = 0.05) difference between the two types of application of the wild types. When cucumber seeds, treated with a T. harzianum rhizosphere-competent mutant (T-95) or its parent wild type (WT), were sown in raw soil kept under constant matric potential with no additional water added, the roots grew 8 cm in 8 days. Untreated seeds produced roots 7 cm long. Fewer colony-forming units of P. ultimum per milligram were isolated from rhizosphere soil of the T-95 treated seedlings than in the untreated controls and those treated with WT. Pythium ultimum was not detected in the 8th cm (farthest from seed) root segment of T-95 treated seeds, whereas the last centimetre of root segment from untreated and WT-treated seeds yielded 3000 colony-forming units/g rhizosphere soil. Seed treatment with rhizosphere-competent mutants of T. harzianum is an effective delivery system to achieve biocontrol and increase growth response.

scholarly journals Disruption of the ech42 (Endochitinase-Encoding) Gene Affects Biocontrol Activity in Trichoderma harzianum P1

1999 ◽  
Vol 12 (5) ◽  
pp. 419-429 ◽  
Author(s):  
S. L. Woo ◽  
B. Donzelli ◽  
F. Scala ◽  
R. Mach ◽  
G. E. Harman ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Trichoderma Harzianum ◽  
Pythium Ultimum ◽  
Single Copy ◽  
Wild Type ◽  
Gene Encoding ◽  
Culture Filtrates ◽  
In Vitro Antifungal Activity ◽  
Better Than

The biocontrol strain P1 of Trichoderma harzianum was genetically modified by targeted disruption of the single-copy ech42 gene encoding for the secreted 42-kDa endochitinase (CHIT42). Stable mutants in which ech42 was interrupted, and unable to produce CHIT42, were obtained and characterized. These mutants lacked the ech42 transcript, the protein, and endochitinase activity in culture filtrates, and they were unable to clear a medium containing colloidal chitin. Other chitinolytic and glucanolytic enzymes expressed during mycoparasitism were not affected by the disruption of ech42. The disrupted mutant D11 grew and sporulated similarly to the wild type. In vitro antifungal activity of the ech42 disruptant culture filtrates against Botrytis cinerea and Rhizoctonia solani was reduced about 40%, compared with wild type; antifungal activity was fully restored by adding an equivalent amount of CHIT42 as secreted by P1. The mutant exhibited the same biocontrol effect against Pythium ultimum as strain P1, but the antagonism against B. cinerea on bean leaves by the mutant was significantly reduced (33% less biocontrol), compared with strain P1. Conversely, the endochitinase-deficient mutant performed better than the wild type (16% improvement of survival) in biocontrol experiments in soil infested with the soilborne fungus R. solani. These results indicate that the antagonistic interaction between the T. harzianum strain and various fungal hosts is based on different mechanisms.

scholarly journals The ThPG1 Endopolygalacturonase Is Required for the Trichoderma harzianum–Plant Beneficial Interaction

2009 ◽  
Vol 22 (8) ◽  
pp. 1021-1031 ◽  
Author(s):  
Eugenia Morán-Diez ◽  
Rosa Hermosa ◽  
Patrizia Ambrosino ◽  
Rosa E. Cardoza ◽  
Santiago Gutiérrez ◽  
...  
Keyword(s):  
Trichoderma Harzianum ◽  
Plant Cell Wall ◽  
Expressed Sequence Tag ◽  
Proteome Analysis ◽  
Pythium Ultimum ◽  
Wild Type ◽  
Trichoderma Spp ◽  
Gene Coding ◽  
Defense Induction

Considering the complexity of the in vivo interactions established by a mycoparasitic biocontrol agent at the plant rhizosphere, proteomic, genomic, and transcriptomic approaches were used to study a novel Trichoderma gene coding for a plant cell wall (PCW)-degrading enzyme. A proteome analysis, using a three-component (Trichoderma spp.–tomato plantlets–pathogen) system, allowed us to identify a differentially expressed Trichoderma harzianum endopolygalacturonase (endoPG). Spot 0303 remarkably increased only in the presence of the soilborne pathogens Rhizoctonia solani and Pythium ultimum, and corresponded to an expressed sequence tag from a T. harzianum T34 cDNA library that was constructed in the presence of PCW polymers and used to isolate the Thpg1 gene. Compared with the wild-type strain, Thpg1-silenced transformants showed lower PG activity, less growth on pectin medium, and reduced capability to colonize tomato roots. These results were combined with microarray comparative data from the transcriptome of Arabidopsis plants inoculated with the wild type or a Thpg1-silenced transformant (ePG5). The endoPG-encoding gene was found to be required for active root colonization and plant defense induction by T. harzianum T34. In vivo assays showed that Botrytis cinerea leaf necrotic lesions were slightly smaller in plants colonized by ePG5, although no statistically significant differences were observed.

Interaction of Glomus fasciculatum and Pythium ultimum on greenhouse-grown poinsettia

1984 ◽  
Vol 62 (8) ◽  
pp. 1575-1579 ◽  
Author(s):  
J. W. Kaye ◽  
F. L. Pfleger ◽  
E. L. Stewart
Keyword(s):  
Root Colonization ◽  
Rhizosphere Soil ◽  
Pythium Ultimum ◽  
Glomus Fasciculatum ◽  
Soil Fertilization ◽  
Potting Medium ◽  
P Content ◽  
Colony Forming Units ◽  
Mn Content ◽  
Mycorrhizal Plants

Rooted Euphorbia pulcherrhima (poinsettia) plants, mycorrhizal with Glomus fasciculatum or nonmycorrhizal, were grown in a potting medium with a phosphorus (P) level of 5 μg/g, containing Pythium ultimum at 0, 38, 66, or 132 colony-forming units (CFU)/g dried soil. Fertilization was at 75 ppm nitrogen–potassium (N–K) weekly. Mycorrhizal root colonization was greater in plants grown in P. ultimum soil at each density than in plants grown in soil without P. ultimum, as determined by the root segment method and at 132 and 38 CFU/g as determined by the root length method. Plant height and foliar P content of mycorrhizal plants were greater than of nonmycorrhizal plants when grown in soil infested with 38 CFU/g P. ultimum. Foliar manganese (Mn) content was greater in nonmycorrhizal than mycorrhizal plants when grown in P. ultimum soil at each density. Mycorrhizal plants had lower final P. ultimum populations in rhizosphere soil than nonmycorrhizal plants when grown in soil infested with 38 CFU/g P. ultimum. Densities of Pythium ultimum were greater in rhizosphere compared with nonrhizosphere soil in the absence of mycorrhizae.

RHYTHMS IN BLUE-LIGHT-INDUCED CONIDIATION OF WILD TYPE AND A MUTANT STRAIN OF Trichoderma harzianum

1988 ◽  
Vol 47 (3) ◽  
pp. 425-431 ◽  
Author(s):  
GERALD F. DEITZER ◽  
BENJAMIN A. Horwitz ◽  
Jonathan Gressel
Keyword(s):  
Blue Light ◽  
Mutant Strain ◽  
Trichoderma Harzianum ◽  
Wild Type

scholarly journals Application of Trichoderma harzianum on the physiological quality of cowpea seeds

2021 ◽  
pp. 643-648
Author(s):  
Marcelo Laranjeira Pimentel ◽  
Henara Valéria Miranda Castro ◽  
Mike Kirixi Munduruku ◽  
Larissa Conceição Cunha Ponte ◽  
Deyvielen Maria Ramos Alves ◽  
...  
Keyword(s):  
Trichoderma Harzianum ◽  
Seed Treatment ◽  
Germination Percentage ◽  
Hypocotyl Length ◽  
Cowpea Seeds ◽  
Randomized Design ◽  
Germination Speed ◽  
Physiological Quality ◽  
Set Up

The use of fungi in seed treatment can improve the plant's physiological characteristics. The aim of this study was to evaluate the influence of the use of Trichoderma harzianum on the physiological quality of bean seeds. The experiment was set up and conducted in the forest seed laboratory of the Federal University of Western Para, in a randomized design, using 4 procedures on the basis of a colony forming unit (CFU): T1 (0 CFU), T2 (4 x 109 CFU), T3 (8 x 109 CFU) and T4 (12 x 109 CFU), with 5 repetitions. Germination percentage (G%), germination speed index (GSI), hypocotyl length (HL) and radicle length (RL) were evaluated as variables. The data were analyzed by variance analysis and the averages were compared using the Tukey test (p≤0.05), in addition to the regression analysis, using the Minitab© version 18 statistical software. There were differences between the germination percentage tests, in which T2 obtained 100% of germinated seeds, for GSI it was observed that T2 and T3 were equal and superior to the other treatments, while for RL T1 and T2 obtained the best results, however, for HL there were no statistical differences between treatments. T2 was more efficient in the physiological quality of seeds to germination percentage and germination speed index

scholarly journals Negative effect of three commonly used seed treatment chemicals on biocontrol fungus Trichoderma harzianum

2014 ◽  
Vol 9 (33) ◽  
pp. 2588-2592 ◽  
Author(s):  
J. Sivparsad B. ◽  
Chiuraise N. ◽  
D. Laing M. ◽  
J. Morris M.
Keyword(s):  
Trichoderma Harzianum ◽  
Seed Treatment ◽  
Negative Effect

Growth of rhizosphere-competent mutants of Trichoderma harzianum on carbon substrates

1988 ◽  
Vol 34 (6) ◽  
pp. 807-814 ◽  
Author(s):  
Jaleed S. Ahmad ◽  
Ralph Baker
Keyword(s):  
Trichoderma Harzianum ◽  
Carbon Sources ◽  
Sole Source ◽  
Ecological Significance ◽  
Wild Type ◽  
Wood Cellulose ◽  
Carbon Substrates ◽  
Rhizosphere Competence ◽  
Complex Carbon ◽  
Root Surfaces

When the strains of Trichoderma harzianum were grown in Czapek-Dox broth without saccharose with cotton linters, microcrystalline cellulose, wood cellulose, or xylan as a sole source of carbon, the rhizosphere-competent mutants produced significantly higher biomass than the rhizosphere-incompetent wild types. Both mutants and wild types did not readily grow on glucose, galactose, cellobiose, or xylose as sole source of carbon. The mutants, T-95 and T-12B, produced significantly higher biomass when grown on complex carbohydrates with added simple sugars. The wild types did not produce significantly greater biomass when both simple and complex sugars were the carbon sources than when either substrate was used alone. The ability of the mutants to grow more rapidly on complex carbon substrates (typical of those found on root surfaces) than their wild-type parents, and to increase biomass when simple sugars were added along with the cellulose substrate could be of ecological significance and a characteristic of rhizosphere competence.

Clonal analysis of deletions on chromosome 20q and JAK2-V617F in MPD suggests that del20q acts independently and is not one of the predisposing mutations for JAK2-V617F

Blood ◽  
2009 ◽  
Vol 113 (9) ◽  
pp. 2022-2027 ◽  
Author(s):  
Franz X. Schaub ◽  
Roland Jäger ◽  
Renate Looser ◽  
Hui Hao-Shen ◽  
Sylvie Hermouet ◽  
...  
Keyword(s):  
Temporal Order ◽  
Jak2 V617f ◽  
Myeloproliferative Disorders ◽  
Genetic Alterations ◽  
Parental Origin ◽  
Wild Type ◽  
Chain Reaction ◽  
Colony Forming Units ◽  
Opposite Order ◽  
Polymerase Chain

We developed a real-time copy number polymerase chain reaction assay for deletions on chromosome 20q (del20q), screened peripheral blood granulocytes from 664 patients with myeloproliferative disorders, and identified 19 patients with del20q (2.9%), of which 14 (74%) were also positive for JAK2-V617F. To examine the temporal relationship between the occurrence of del20q and JAK2-V617F, we performed colony assays in methylcellulose, picked individual burst-forming units–erythroid (BFU-E) and colony-forming units–granulocyte (CFU-G) colonies, and genotyped each colony individually for del20q and JAK2-V617F. In 2 of 9 patients, we found that some colonies with del20q carried only wild-type JAK2, whereas other del20q colonies were JAK2-V617F positive, indicating that del20q occurred before the acquisition of JAK2-V617F. However, in colonies from 3 of 9 patients, we observed the opposite order of events. The lack of a strict temporal order of occurrence makes it doubtful that del20q represents a predisposing event for JAK2-V617F. In 2 patients with JAK2-V617F and 1 patient with MPL-W515L, microsatellite analysis revealed that del20q affected chromosomes of different parental origin and/or 9pLOH occurred at least twice. The fact that rare somatic events, such as del20q or 9pLOH, occurred more than once in subclones from the same patients suggests that the myeloproliferative disorder clone carries a predisposition to acquiring such genetic alterations.

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