Investigation of hydrophobin genes of entomopathogenic fungi, determination of hydrophobin-infectivity relationship and expression in the in vitro system

Hydrophobins are cysteine-rich, amphipathic proteins produced in filamentous fungi with a molecular mass of about 10 kDa. Because of these properties, they play an important role in many industrial applications such as surface coatings, biosensors, purification of recombinant proteins and self-cleaning surfaces. In this thesis, it was aimed to determine the hydrophobin genes found in entomopathogenic fungi (EPF), to compare the hydrophobin properties and insecticidal properties, and to prepare the selected hydrophobin gene for industrial use by expressing it in Pichia pastoris yeast system. For this purpose, the presence of hydrophobin gene was investigated in 20 entomopathogenic fungus isolates obtained from the fungus collection of Karadeniz Technical University, and the hydrophobin gene (hyd) was detected in 14 of these isolates. It was determined that all isolates carrying the hydrophobin gene belong to the class I hydrophobin group. When the entomopathogenic fungi containing the hydrophobin gene were evaluated, considering the insecticidal activity, morphological features, rapid growth, host spectrum, degree of adhesion on the host surfaces and high mortality, it was decided to express the hydrophobin gene of Beauveria bassiana KTU-57 in the P. pastoris yeast system. In this direction, ribosomal RNA was obtained from the fungal genome and its cDNA was created with the reverse transcriptase enzyme. The hydrobin gene obtained by RT-PCR (Reverse Transcriptase-Reverse Transcriptase) was cloned into the pPICZC vector and expression of the recombinant yeast vector (pPICZC+hyd) in the P. pastoris X-33 gene expression host was achieved. Although a significant amount of protein expression has been achieved, optimization studies are continuing to increase the production capacity for the industrial use of hydrophobin protein.