Estudos bioquímicos e moleculares de genes de trichoderma envolvidos no mecanismo de micoparasitismo
Carregando...
Data
2012-03-30
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
Species of Trichoderma are commercially applied as biological control agents and are
antagonists of important plant pathogenic fungi (as Rhizoctonia, Sclerotinia and Fusarium
species) due to its mycoparasitic characteristics. Research has been performed to have a
better comprehension of molecular aspects of the biocontrol mechanisms performed by
Trichoderma and to find isolates with high antagonistic potential against plant pathogens. In
the present study the expression of mycoparasitism-related genes was performed T.
asperellum T00 and T. harzianum ALL42 (Enzimologia group ICB/UFG fungal collection) that
have great potential as biocontrol agent. Each chapter of this work refers to one of the
species studied. In Chapter 1 T. asperellum isolate T00, known to produce high levels of cell
wall degrading enzymes, has its β-1,3-glucanases enzymes and genes (tag83 and tag27)
studied. The gene tag27 was cloned and characterized and codes to an 27kDa endo-β-1,3glucanase
with and 285 aminoacids and 96% similar to a glucanases from T.atroviride. The
enzyme was detected when T. asperellum was grown in Rhizoctonia solani or Sclerotinia
sclerotiorum cell wall-containing media but not in Fusarium oxysporum cell wall-containing
media. The tag83 and tag27 genes was repressed in media containing glucose as carbon
source and upregulated in cell wall containing media and during plate confrontation tests with
pathogenic fungi. Chapter 2 shows T. harzianum isolate ALL42 genes involved in
mycoparasitism against R. solani or S. sclerotiorum detected using subtractive hybridization
approach. T. harzianum was grown with R. solani or S. sclerotiorum cell wall as carbon
source and the RNA used both as tester and driver in each of two subtractive library
constructed. Sequencing analysis resulted in 47 genes related with growth in R. solani cell
wall media and 114 genes related with growth in S. sclerotiorum cell wall media. To confirm
the obtained data, 18 genes were tested by quantitative real time RT-PCR and 9 were
differentially expressed in the same condition of the library they were detected. Five of these
genes were also differentially expressed during plate confrontation assay with the respective
pathogen, two of them expressed during contact with R. solani (cutinase and alginate lyase)
and 3 during contact with S. sclerotiorum (hsp98, serin endopeptidase and a hypotetic gene).
The results presented in this study provides additional information about the role of 1,3glucanase
genes in mycoparasitism and of other genes related to antagonism against
specific pathogens, providing helpful insights in the mechanism of biocontrol performed by
Trichoderma.
Descrição
Palavras-chave
Citação
SIQUEIRA, Saulo José Linhares de. Estudos bioquímicos e moleculares de genes de trichoderma envolvidos no mecanismo de micoparasitismo. 2012. 110 f. Tese (Tese em Biologia ) - Universidade Federal de Goiás, Goiânia, 2012.