Understanding Beauveria bassiana infection within its host Triatoma infestans: time course expression of genes encoding fungal toxic nonribosomal peptides and insect humoral immune proteins

L.S. LOBO; E.K.K. FERNANDES; C. LUZ; M. P. JUAREZ; N. PEDRINI

Mainz

Congreso; 47th Annual Meeting of the Society for Invertebrate Pathology. 2014 International Congress on Invertebrate Pathology and Microbial Control; 2014

Society for Invertebrate Pathology

During invasion into insect hemocoel, some entomopathogenic fungi secrete toxins contributing to a successful infection. In response, insect cellular and humoral immune reactions are triggered. In this work, we studied by real-time PCR the expression pattern of B. bassiana genes involved in beauvericin, bassianolide, and tenellin biosynthesis throughout the infection process in nymphs of the kissing bug T. infestans. We also investigated the expression level of some bug proteins involved in the humoral immune response, i.e. prophenoloxidase, hemolectin and defensin. In conidia-treated insects, the expression of beauvericin synthetase, bassianolide synthetase, and tenellin synthetase peaked 6 days post-inoculation. In blastospore-injected bugs (bypassing the insect cuticle) the expression level peaked 12 hours post-injection. Regarding insect immune response, conidia treatment induced higher expression of defensin and hemolectin, with values of 8.3 ± 1.1 and 2.7 ± 1.4 fold inductions, respectively. In blastospore-treatment, the expression level of all genes tested raised from 12 to 48 hours, reaching 9.3 ± 3.6 (prophenoloxidase) and 26.6 ± 5.4 (defensin) fold induction. These results help to understand at the molecular level the ?arm race? taking place in insect hemocoel during fungal invasion.