进食状态介导桔小实蝇嗅觉可塑性性别差异的机理研究

Plasticity in insect olfactory is that insect could modulate their olfactory behaviors according to their physiological state upon interaction with their environment. Insect responses to biologically active chemical stimuli may vary not only according to biotic and abiotic environmental factors or previous experience, but also as a function of the physiological state, including age, feeding state and circadian rhythm. Methyl eugenol is one of the most widely used attractants to control and monitor Bactrocera dorsalis. In our study, we found that the starvation treatment could increase the attractive efficacy of methyl eugenol against female B.dorsalis, however, feeding state is independent to its effect against male B.dorsalis. The mechanism of such sexual differences on plasticity in olfactory of B.dorsalis induced by feeding state remains elusive. In this project, the olfactory receptor and olfactory sensory neuron to specifically recognize methyl eugenol in female and male B.dorsalis will be identified, respectively. To illuminate the mechanism of differences on olfactory plasticity between female and male B.dorsalis, the variations in expression and distribution of target odorant receptor and the sensitivities of olfactory sensory neurons in different starvation treatments of B.dorsalis will be examined. The expected result could provide new insights into the study of plasticity in olfactory, and provide effective strategies and techniques to increase the effect of methyl eugenol against female B.dorsalis, and expand applicable scope of methyl eugenol in field.

昆虫嗅觉可塑性是指昆虫依据其不同生理状态、外界环境和自身成长经历，改变原有的嗅觉行为的能力。甲基丁香酚是桔小实蝇的高效引诱剂，前期研究发现，饥饿处理可显著提高甲基丁香酚对桔小实蝇雌虫的引诱效果，但对雄虫的引诱力无影响。桔小实蝇这种进食状态介导的嗅觉可塑性性别差异的行为机制尚无报道。本项目拟鉴定雌/雄桔小实蝇识别甲基丁香酚的靶标嗅觉神经元和气味受体，明确在雌雄个体之间识别甲基丁香酚的嗅觉通路是否存在差异，并挖掘不同进食状态下，雌雄虫对引诱剂的响应能力产生差异的原因，最终阐明进食状态介导桔小实蝇对引诱剂的嗅觉响应存在性别差异的分子机制，理论上帮助我们丰富对昆虫生理状态介导嗅觉行为塑造的认知，实际应用上为有效提高甲基丁香酚对雌性桔小实蝇的引诱效果提供策略和方法，为合理使用甲基丁香酚提供依据。

昆虫嗅觉可塑性是指昆虫依据其不同生理状态、外界环境和自身经历改变原有的嗅觉行为的能力。甲基丁香酚是桔小实蝇的高效引诱剂，前期研究结果发现，饥饿处理可显著降低雄性桔小实蝇对甲基丁香酚的识别反应力。本项目针对该现象开展深入研究：多种行为学观察进一步明确饥饿处理对桔小实蝇识别甲基丁香酚的选择偏好性有影响；通过触角封蜡试验和RNA干扰试验明确桔小实蝇识别甲基丁香酚是通过嗅觉系统介导的；通过RNAi结合行为学观察筛选鉴定桔小实蝇识别甲基丁香酚的关键嗅觉受体为Or12a和Or12c；筛选获得胰岛素通路的叉头框转录因子FoxO是饥饿处理影响桔小实蝇嗅觉识别敏感性的关键因子，可在转录水平调控关键识别受体的表达，从而影响桔小实蝇对甲基丁香酚的识别敏感性。本研究结果在分子水平上解析饥饿处理影响桔小实蝇嗅觉识别敏感性的具体机制，丰富了对昆虫生理状态介导的嗅觉行为可塑性的认知，并为有效提高甲基丁香酚对桔小实蝇的引诱效率提供策略和方法。