Análise da expressão dos genes ThHsp70a, ThHsp70b e ThHsp70c de Trichoderma harzianum durante o micoparasitismo e estresse térmico

Abstract

The filamentous fungus Trichoderma harzianum is part of a genus of fungi that act as agents of biological control, widely used against some phytopathogens, such as Sclerotinia sclerotiorum. This relationship of mycoparasitism, leads to certain stresses on the cells of Trichoderma, provoking a response, which occurs through changes in cellular metabolism, activating defense mechanisms through heat shock proteins (Hsp). This work aimed to analyze the expression of genes encoding heat shock proteins of the HSP70 family of T. harzianum during myoparasitism and in the response to thermal and oxidative stresses. The total RNA was extracted from mycelium of T. harzianum and the Δepl-1 mutant under pre-contact conditions (precontact), during (contact) and after contact (contact) with the phytopathogen S. sclerotiorum. Total RNA was also extracted from T. harzianum cells subjected to temperature and ethanol stress. Then, qRT-PCR was used to assess the level of expression of ThHsp70a, ThHsp70b and ThHsp70c genes during the conditions tested. Expression of ThHsp70a, ThHsp70b and ThHsp70c genes has been observed to vary according to the phases of mycoparasitism. The data suggest that the mechanism of self-recognition of T. harzianum is important for the activation of the gene expression of ThHsp70b and ThHsp70c. All genes were induced by heat shock, showing the ThHsp70a and ThHsp70c genes at the highest mRNA levels. During stress with ethanol, ThHsp70a was the gene that presented the highest induction.