Zhang Zhongjie, Liu Xiaojing, Chen Mengdan, Sun Chenxin, Zhu Dalin, Lei Jialong, He Qingyun, Yan Qi, Dong Shuanglin, Tan Anjiang
Jiangsu Key Laboratory of Sericultural and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212100, China.
Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Scientific Research Center, Chinese Academy of Agricultural Sciences, Zhenjiang, 212100, China.
BMC Biol. 2025 Aug 15;23(1):256. doi: 10.1186/s12915-025-02352-2.
Gustatory receptors (GRs) are known to mediate responses to various chemical stimuli including sugars and bitter compounds and sex pheromones. Although numerous types of GRs have been identified across insect species, the physiological roles of most GRs remain largely unknown. The silkworm, Bombyx mori, is representative of the order Lepidoptera, which includes over 70% of agriculturally important pest species. A notable feature of GRs in B. mori is that most GRs are organized in clusters, making them highly suitable for large-scale genetic studies.
Here we developed a transcription activator-like effector nuclease-mediated gene cluster replacement system, enabling functional studies beyond single-gene resolution. Using this system, we deleted the GR27-31 cluster in B. mori, which includes 12 GRs spanning approximately 82 kb of genomic sequence. Loss of GR27-31 function results in significant time retardation of courtship by impairing the ability of male silkmoths to seek female silkmoths. Electroantennogram analysis revealed that GR27-31 mutant male silkmoths did not change their responses to volatile sex pheromones of bombykol and bombykal compared with wild-type silkmoths, indicating that GR27-31 mutation did not affect male-female sex pheromone responses at the peripheral level. Subsequent molecular analysis revealed that mRNA relative expression of serotonin receptors was significantly affected in mutant silkmoths.
The current study provides the first genetic and phenotypic evidence that GRs modulate male-female courtship in B. mori. Furthermore, the results revealed for the first time that the serotonin pathway is associated with GR regulation of courtship behavior in insects.
味觉受体（GRs）已知可介导对各种化学刺激的反应，包括糖类、苦味化合物和性信息素。尽管在昆虫物种中已鉴定出多种类型的GRs，但大多数GRs的生理作用仍 largely未知。家蚕（Bombyx mori）是鳞翅目昆虫的代表，该目包括超过70%的农业重要害虫物种。家蚕GRs的一个显著特征是大多数GRs成簇组织，这使得它们非常适合进行大规模遗传研究。
在此，我们开发了一种转录激活样效应核酸酶介导的基因簇替换系统，能够进行超越单基因分辨率的功能研究。使用该系统，我们在家蚕中删除了GR27 - 31基因簇，该基因簇包含12个GRs，跨越约82 kb的基因组序列。GR27 - 31功能丧失导致雄蚕蛾寻找雌蚕蛾的能力受损，从而使求偶时间显著延迟。触角电位分析表明，与野生型蚕蛾相比，GR27 - 31突变型雄蚕蛾对蚕蛾醇和蚕蛾醛挥发性性信息素的反应没有改变，这表明GR27 - 31突变在外周水平上不影响雌雄之间的性信息素反应。随后的分子分析表明，突变蚕蛾中血清素受体的mRNA相对表达受到显著影响。
本研究提供了首个遗传学和表型证据，证明GRs在家蚕中调节雌雄求偶行为。此外，结果首次揭示血清素途径与昆虫求偶行为的GR调节有关。
