Kou Jing,Zhu Zheng-Yang,Wang Su,Zhang Yu,Wang Jie,Jaworski Coline C.,Harwood James D.,Jing Lan,Desneux Nicolas,Di Ning
The heavy metal cadmium (Cd) leads to significant bottom-up effects on food chains of plants, herbivores, and predators in agroecosystems. Through the transfer and accumulation of Cd. In addition to the indirect effects of this cascading effects, predators Orius sauteri fed with artificial diets containing Cd also have a direct effect. We found that O. sauteri fed with sucrose solutions containing Cd at high concentrations of 125 mg/L and 625 mg/L significantly decreased the survival of the 3rd and 5th instar, female, and male adults (except 125 mg/L) of O . sauteri . However, the survival of O. sauteri nymphs was significantly increased when they fed with low concentrations of 1 mg/L, 5 mg/L and 25 mg/L Cd sucrose solutions. Cd stress has differing effects on the LC 50 of each age of O. sauteri , the lowest LC 50 for male adults (153 mg/L), followed by 3rd instar nymphs (192 mg/L), 5th instar nymphs (289 mg/L) and female adults (383 mg/L). It is interesting that 1 mg/L, 5 mg/L, and 25 mg/L of sucrose solutions containing Cd significantly improved the predation capacity of the nymphs of O. sauteri to the B emisia tabaci pupa. The predation ability of the male adults of O . sauteri on B . tabaci pupa were significantly improved, but significantly decreased in the female adults when they fed with 125 mg/L and 625 mg/L sucrose solutions containing Cd. This difference needs to be studied in depth in the future, controlling Cd contamination and protecting natural enemies to enhance the biological control of pests. Graphical Abstract
Zhe-Ran Wu,Yi-Wen Pei,Xiao-Qing Zhang,Min Lu,Xiao-Long Liu
Chemical sensing systems are vital in the growth and development of insects. Orius sauteri (Poppius) (Hemiptera: Anthocoridae) is an important natural enemy of many pests. The molecular mechanism of odorant binding proteins (OBPs) binding with common insecticides is still unknow in O. sauteri . In this study, we expressed in vitro OsauOBP8 and conducted fluorescence competition binding assay to investigate the function of OsauOBP8 to insecticides. The results showed that OsauOBP8 could bind with four common insecticides (phoxim, fenitrothion, chlorpyrifos, deltamethrin). Subsequently, we used molecular docking to predict and obtained candidate six amino acid residues (K4, K6, K13, R31, K49, K55) and then mutated. The result showed that three key residues (K4, K6, R31) play important role in OsauOBP8 bound to insecticides. Our study identified the key binding sites of OsauOBP8 to insecticides and help to better understand the molecular mechanism of OBPs to insecticides in O. sauteri .
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