Study on the gene expression of Chit1 and Chit2 in Beauveria bassiana during the parasitic interaction with onion thrips, Thrips tabaci (Thys.: Thripidae)

The host-pathogen interaction is a very complex process. Like many entomopathogenic fungi during infection process، Beauveria bassiana produces enzymes which are able to destroy the cuticle of insects in order to penetrate into the host. Chitinases are considered to be the important enzymes for the hydrolysis of chitin and play an important role in the biological control of various pests including onion thrips، Thrips tabaci Lind. In the present study، specific primers for CHit1 and CHit2 genes were designed to study the expression pattern of these two chitinases from B. bassiana IRAN 789C strain before and after interaction with the second instar larvae of onion thrips using RT-PCR. Larval inoculation was carried out using three concentrations، 104، 105 and 106 conidia per ml. The results showed that both genes were expressed in all conidial concentrations، after parasitic interaction. Increasing the conidial concentration of B. bassiana caused the upregulation of chitinases expression level. Expression of these genes during the parasitic interaction of the fungus and insect larvae reflects the importance of chitinases gene as an effective factor in biological control of target organisms.