Showing papers on "Trichoderma longibrachiatum published in 1994"

Morphological and macromolecular characterization of Hypocrea schweinitzii and its Trichoderma anamorph

Abstract: Morphological, cultural, and isozyme anal- yses were used to determine variation in the Tricho- derma anamorph of Hypocrea schweinitzii, a presumably unequivocal species of Trichoderma, and to assess whether the anamorph of H. schweinitzii can be as- signed to T. longibrachiatum, T reesei, or T. pseudoko- ningii. The results of these studies indicate that H. schweinitzii comprises at least three distinct and tax- onomically separable holomorph taxa that coincide with the geographical origin of the collections. The name H. schweinitzii can be applied to Northern Hemi- sphere and H. jecorina to tropical American collec? tions; while taxonomically distinct, no name was given to a Chinese collection. The holomorphs of H. schwei? nitzii, H. jecorina, and the Chinese collection showed little intraspecific variation in morphology of the teleo- morph or anamorph, or in cultural and isozyme char- acters. They exhibited no more variation than was noted in the ex type cultures of the named Trichoderma species. None of the named Trichoderma species co- incided with any of the Hypocrea species studied. It is concluded that Trichoderma species in general can be narrowly defined but that morphology alone might not suffiee to allow the identification of species. The syn-

Novel cellulase enzymes and systems for their expression

Abstract: The present invention relates to the cloning and high level expression of novel truncated cellulase proteins or derivatives thereof in the filamentous fungus Trichoderma longibrachiatum. Further aspects of the present invention relate to fungal transformants that express the novel truncated cellulases and derivatives, and expression vectors comprising the DNA gene fragments or variants thereof that code for the truncated cellulases derived from Trichoderma longibrachiatum using genetic engineering techniques.

Development of a transformation system for Trichoderma longibrachiatum and its use for constructing multicopy transformants for the egl1 gene.

Abstract: An efficient transformation system for the fungusTrichoderma longibrachiatum has been developed. Transformation was obtained both by electroporation and polyethyleneglycol treatment, using a plasmid carrying theEscherichia coli hygromycin B phosphotransferase gene as a dominant selectable marker. The transformation frequency was 0.5 to 5 transformants /μg plasmid DNA. Transformation normally occurred by tandem integration of the transforming DNA. A high percentage of the transformants were mitotically unstable. The efficiency of co-transformation was very high (around 90%), and several co-transformants containing multiple copies of theegll gene encoding a β-(1,4)-endoglucanase were obtained. Some of them secrete increased levels of endoglucanase to the culture medium. In addition, theE. coli lacZ gene was expressed in an active form under control of theAspergillus nidulans gpdA gene promoter.

Interaction between Trichoderma species and Armillaria root rot fungus of tea in Kenya

Abstract: The interaction of 11 Trichoderma isolates against Armillaria root rot fungus of tea was investigated. Most isolates significantly inhibited the growth of Armillaria. The highest inhibition was noted with one of the isolates of T. koningii, T. longibrachiatum and T. harzianum. The isolates with highest inhibitory properties tended to produce a pigment into the nutrient broth. The implications of these results in view of the future management strategies of Armillaria root rot of tea in Kenya are discussed.

Purification and molecular cloning of eg iii cellulase

Abstract: The present inventon is directed to purified EG III cellulase enzyme isolated from Trichoderma longibrachiatum and the amino acid sequence of the secreted (mature) and non-secreted (preprotein) forms. The present invention is further directed to the DNA fragment and sequence that encodes the EG III cellulase enzyme. Also disclosed are methods for isolating either purified or highly enriched EG III cellulase obtained from Trichoderma spp. or genetically modified strains of $i(Trichoderma spp.)

Transcriptional regulation of the Trichoderma longibrachiatum egl1 gene

Abstract: Transcription of the Trichoderma longibrachiatum egl1 gene is induced in the presence of lactose and β-methylglucoside and repressed by glucose. A DNA fragment containing 722 bp upstream of the ATG codon has been sequenced. The gene has two major transcription start points (20 and 24 nucleotides upstream from the ATG codon) and several transcription termination points (located in a region around 130 nt downstream of the stop codon). Two 6-mer sequences (5′-CTGGAG-3′) separated by 16 bp are present in the egl1 gene promoter. These sequences match the Aspergillus nidulans consensus CreA binding site and might be implicated in carbon catabolite repression of egl1 transcription.

Hypercellulolytic Transformants of Trichoderma Longibrachiatum are Active in Reducing Pythium Damping-Off on Cucumber

Abstract: Imperfect fungi in the genusTrichoderma are among the most promising biocontrol agents against a wide range of plant pathogenic fungi[1,2] Their biological control activity involves, among other mechanisms proposed, mycoparasitism, which can be accomplished through the production of lytic enzymes: chitinases, together with βglucanases and proteases, are considered to be the most critical in mycoparasitism[2,3]Correlation between the production of chitinolytic enzymes and the biocontrol of fungi containing chitin as the main cell wall constituent has been demonstrated for many Trichoderma species [4,9]. On the contrary, little is known about the role of cellulolytic enzymes in the biocontrol of plant pathogenic Oomycetes, which contain cellulose as the main cell wall component [10].