Caracterizaçãoda alfa-manosidase produzida por Trichoderma harzianum durante o micoparasitismo
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2015-08-28
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Universidade Federal de Goiás
Resumo
Fungi of the genus Trichoderma have emerged as biological control agents,
especially those belonging to the species Trichoderma harzianum with various
mechanisms involved include production of antibiotics, mycoparasitism, competition
for nutrients and host plant resistance induction. Mycoparasitism is a sequential
process that involves recognition of the host contact, adhesion, expression of specific
genes and secretion of secondary metabolites. Several hydrolytic enzymes are
involved in this process among them chitinases, beta-glucanases and proteases.
Recent studies of T. harzianum interaction with some pathogens have shown that
other enzymes may also be involved in this mechanism, among which alphamannosidase.
Alpha-mannosidase has an essential role in the recycling of
glycoproteins in filamentous fungi, but little is known about the role of these enzymes
in mycoparasitism. This study aims to characterize the expression of T. alphamannosidase
gene harzianum after growth in cell wall of Sclerotinia sclerotiorum
(SS), Fusarium solani (FS) and Fusarium oxysporum (FO) as well as during the
interaction in vivo . It was used as a control cell wall T. harzianum (TH). Also, jobs
obtaining mutants of this gene in T. harzianum were performed. Our data show that
alpha-mannosidase gene was highly expressed as T. harzianum grown in the
presence of cell wall SS (4.5X), FS (18X) and FO (75X) compared to the control TH
(1X). In comparison situation it was noticed a 75X greater expression in TH x FO
state during contact as compared with the control (TH x TH). In other situations of
confrontation did not observe a significant increase in expression. The promoter
region, the selection mark and the terminator region of the alpha-mannosidase of T.
harzianum gene was cloned into the pRS426 vector, and the deletion cassette was
assembled by the recombination technique in Saccharomyces cerevisiae. Then,
these vectors were used for transformation of T. harzianum and transformants were
obtained by selection on plates containing hygromycin b. Approximately 50
transformants were obtained, but none of the alpha-mannosidase gene was
successfully deleted. Obtaining more transformants is necessary for us to have a
mutant alpha-mannosidase gene deleted.
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MOTA, P. R. Caracterizaçãoda alfa-manosidase produzida por Trichoderma harzianum durante o micoparasitismo. 2015. 54 f. Dissertação (Mestrado em Biologia) - Universidade Federal de Goiás, Goiânia, 2015.