Chemosensory proteins participate in insecticide susceptibility in Rhopalosiphum padi, a serious pest on wheat crops.

Rhopalosiphum padi is a worldwide agricultural pest. Chemosensory proteins (CSPs) are considered to be a type of transporters which can bind chemicals from external environments. Previous research showed that the expression of some insect CSPs were significantly increased after exposure to insecticides, and CSPs were involved in insecticide resistance or susceptibility. However, the role of CSPs in the susceptibility and response of R. padi to insecticides is still unknown. In this study, we identified eight CSP (RpCSP) from R. padi by genome-wide investigation. Seven RpCSP genes had two exons, while RpCSP7 had three exons. qPCR analyses showed that the mRNA levels of the eight RpCSP genes were significantly affected by imidacloprid and beta-cypermethrin in different post-treatment periods. Molecular docking predicted that there were hydrogen bonding sites which played key roles in binding of RpCSP4, RpCSP5, RpCSP6, RpCSP7 and RpCSP10 with imidacloprid and beta-cypermethrin. Knockdown of RpCSP4, RpCSP5, RpCSP6 and RpCSP10 by RNA interference significantly increased the aphid mortality under two sublethal concentrations of imidacloprid. Mortalities under two sublethal concentrations of beta-cypermethrin conditions were significantly higher after injection of R. padi with dsCSP4 and dsCSP6. The results indicate that some RpCSP genes are involved in the insecticide susceptibility of R. padi.

Utilization of isolated marine mussel cells as an in vitro model to assess xenobiotics induced genotoxicity.

Freshly isolated cells are used as an ideal experimental model in in vitro toxicology analysis, especially the detection of diverse xenobiotics induced genotoxic effects. In present study, heavy metals (Zn, Cu, Cd, Pb) and PCBs were selected as representative xenobiotics to verify the ability of in vitro model in assessing genotoxic effects in cells of marine mussels (Mytilus galloprovincialis). DNA damage and chromosome aberration were assessed in freshly isolated cells from haemolymph, gill and digestive gland by single cell gel electrophoresis and micronucleus assay respectively. Gill cells showed more sensitive to Zn exposure among three types of cells, indicating tissue-specific genotoxicity. Significantly higher DNA aberrations were induced by Cu in haemocytes compared to Cd and Pb, indicating chemical-specific genotoxicity. An additive effect was detected after combined heavy metals and PCBs exposure, suggesting the interaction of selected xenobiotics. To our knowledge, this is the first attempt to study the complex effects of organic and/or inorganic contaminants using freshly isolated cells from marine mussels. Genetic responses are proved to occur and maintained in vitro in relation to short-term xenobiotics induced stresses. The utilization of the in vitro model could provide a rapid tool to investigate the comprehensive toxic effects in marine invertebrates and monitor environmental health.