Jack bean urease impairs oogenesis in the Chagas disease vector Rhodnius prolixus

Jack Bean Urease (JBU) is a urease isoform from the plant Canavalia ensiformis with recognized insecticidal properties, although its full entomotoxic potential remains poorly understood. In this study, we used Rhodnius prolixus, a vector of Chagas disease, as a model to investigate the effects of JBU on reproduction. Injection of a sublethal dose in vitellogenic females significantly reduced oviposition and delayed ovarian development, with ovarioles displaying degenerating follicles. Microscopy analyses revealed signs of apoptosis, autophagy, and necrosis in the ovarian tissue of JBU-treated insects. The fat body-the main sites of vitellogenin and lipophorin synthesis-exhibited necrotic features, enlarged adiposomes, and increased triacylglycerol content. qPCR analysis showed increased transcript levels of the lipid metabolism-related genes acetyl-CoA carboxylase, perilipin, and Brummer lipase in JBU-treated females. ELISA assays indicated that JBU induced changes in the amounts of vitellogenin and lipophorin in the fat body and the ovary, as well as in their levels in the hemolymph. JBU treatment impaired vitellogenin uptake and lipophorin-mediated lipid transfer to the oocytes while promoting lipid accumulation in the fat body. An in vivo approach using fluorescently labeled JBU showed its presence in the fat body and ovarian tissues, with no detectable proteolytic processing of JBU in the hemolymph under the conditions tested. Altogether, these findings indicate that JBU-induced reproductive impairment is, at least in part, mediated by disruptions in lipid metabolism along the fat body-ovary axis. These results contribute to understanding the entomotoxic effects of JBU and highlight its potential impact on insect population dynamics.