Insect gustatory system plays important roles in multiple behaviors including feeding, mating, and oviposition. Gustatory receptors (GRs), located on the dendritic membrane of gustatory sensory neurons (GSNs), are crucial in peripheral coding of non-volatile compounds. However, GRs and their detailed functions remain poorly understood in lepidopteran pests. In the present work, focusing on GR genes of Plutella xylostella, an important worldwide crop pest, we cloned a candidate fructose GR gene that has two spliced variants (PxylGR43a-1 and PxylGR43a-2), and determined the tissue expression profiles by semi-quantitative reverse transcription PCR (RT-PCR). It revealed that both GR variants were highly expressed in antennae and less highly in heads of adults, while PxylGR43a-2 was also weakly expressed in other tested tissues. Functional analyses were further conducted using the Xenopus oocyte system. PxylGR43a-1 and PxylGR43a-2 both responded specifically to the d-fructose among the 12 tested sugar compounds, but PxylGR43a-2 showed much higher current response than PxylGR43a-1. In addition, the proboscis extension reflex (PER) assay was conducted, demonstrating that female moths could respond to d-fructose following stimulation of antenna. Taken together, our study contributes to elucidation of the molecular mechanisms of fructose reception and provides a potential target for development of GR based pest control techniques.

中文翻译：

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小菜蛾 Plutella xylostella 果糖味觉受体两个剪接变体的功能表征

昆虫的味觉系统在包括进食、交配和产卵在内的多种行为中起着重要作用。味觉受体 (GRs) 位于味觉感觉神经元 (GSN) 的树突膜上，在非挥发性化合物的外周编码中至关重要。然而，对鳞翅目害虫的遗传资源及其详细功能仍知之甚少。在目前的工作中，我们重点研究了世界范围内重要的农作物害虫 Plutella xylostella 的 GR 基因，克隆了一个候选果糖 GR 基因，该基因具有两个剪接变体（PxylGR43a-1 和 PxylGR43a-2），并通过半定量逆转录 PCR (RT-PCR)。结果表明，这两种 GR 变体在成虫的触角中高度表达，而在成虫头部中表达较少，而 PxylGR43a-2 在其他测试组织中的表达也较弱。使用非洲爪蟾卵母细胞系统进一步进行功能分析。PxylGR43a-1 和 PxylGR43a-2 都对 12 种测试糖化合物中的 d-果糖有特异性响应，但 PxylGR43a-2 显示出比 PxylGR43a-1 高得多的电流响应。此外，进行了长鼻伸展反射 (PER) 测定，证明雌性飞蛾可以在触角刺激后对 d-果糖作出反应。总之，我们的研究有助于阐明果糖接收的分子机制，并为开发基于 GR 的害虫防治技术提供潜在目标。进行了长鼻伸展反射 (PER) 测定，证明雌性飞蛾可以在触角刺激后对 d-果糖作出反应。总之，我们的研究有助于阐明果糖接收的分子机制，并为开发基于 GR 的害虫防治技术提供潜在目标。进行了长鼻伸展反射 (PER) 测定，证明雌性飞蛾可以在触角刺激后对 d-果糖作出反应。总之，我们的研究有助于阐明果糖接收的分子机制，并为开发基于 GR 的害虫防治技术提供潜在目标。