RNA interference (RNAi) is powerful biotechnology for studying the in vivo functions of key genes. Based on this property, RNAi can also be used for pest control as an effective alternative to chemical pesticides. The management of phloem-sucking pests is a tricky issue in current agricultural and forestry pest control. RNAi can silence key chemoreceptor genes of phloem-sucking pests; thereby regulating the behavior of these pests can be manipulated. So, it is considered to be a promising new type of ecological pest management strategy. In this study, we identified a candidate taste receptor gene, BtGR11, that controls the taste sensitivity to sucrose in the whitefly Bemisia tabaci, which is a serious invasive phloem-sucking pest worldwide. Functional analyses using the Xenopus oocyte expression system and the two-electrode voltage-clamp system revealed that the oocytes expressing BtGR11 responded to sucrose. Furthermore, we found that silencing BtGR11 by RNAi inhibited the function of sensing sucrose in the whitefly. This study reports a key chemoreceptor gene that can be used for the understanding of the gustatory sensing mechanisms of whitefly to deterrent.

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Fatty acyl‐CoA reductases (FARs) play an important role in the synthesis of fatty alcohols in various organisms. Based on the important function of FAR genes, they can be used as a potential molecular target for controlling agricultural pests. Although the FAR genes have been studied in a number of insects, the gain, loss, and molecular evolution of FAR genes between different Hemipteran species still require comprehensive and systematic study. This study systematically identified and analysed 352 FAR genes from 12 Hemipteran species, including six typical true bug species, Cimex lectularius, Apolygus lucorum, Halyomorpha halys, Oncopeltus fasciatus, Rhodnius prolixus and Gerris buenoi. The number of FAR genes per species ranged from 17 to 43, and a phylogenetic analysis showed that the identified FAR genes of Hemiptera can be classified into 11 clades. The gain and loss of FAR genes have occurred in some Hemipteran species. These FAR genes conform to the birth‐and‐death model in the evolutionary process. Through selection pressure analysis, we determined that G. buenoi in clade 11 evolved under the pressure of positive selection, with the evolutionary sites of A at position 214 and T at position 451, thus clarifying the differences in amino acids among species and providing a better understanding of the molecular evolutionary mechanism of Hemipteran FAR. In addition, structural analysis of the FAR genes revealed duplication of the two conservative domains, the Rossmann‐fold domain and the sterile domain, of the FAR in four species, namely Bemisia tabaci, Diaphorina citri, R. prolixus and Trialeurodes vaporariorum. This study lays a foundation for further studies on the molecular functions of Hemiptera FAR, and provides a possible new target for the control of Hemiptera, especially the stink bugs.