Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, People's Republic of China.
Parasit Vectors. 2022 Apr 23;15(1):143. doi: 10.1186/s13071-022-05259-x.
The olfactory system plays a crucial role in regulating insect behaviors. The detection of odorants is mainly mediated by various odorant receptors (ORs) that are expressed in the dendrites of olfactory neurons of chemosensilla. Anopheles sinensis is a major malaria vector in Eastern Asia and its genome has recently been successfully sequenced and annotated. In this study, we present genome-wide identification and expression profiling of OR genes in different chemosensory tissues of An. sinensis.
The OR genes were identified using the available genome sequences of An. sinensis. A series of bioinformatics analyses were conducted to investigate the structure, genome distribution, selective pressure and phylogenetic relationships of OR genes, the conserved domains and specific functional sites in the OR amino acid sequences. The expression levels of OR genes were analyzed from transcriptomic data from An. sinensis antennae, proboscis and maxillary palps of both sexes.
A total of 59 putative OR genes have been identified and characterized in An. sinensis. This number is significantly less than that in An. gambiae. Whether this difference is caused by the contraction or expansion of OR genes after divergence of the two species remains unknown. The RNA-seq analysis showed that AsORs have obvious tissue- and sex-specific expression patterns. Most AsORs are highly expressed in the antennae and the expression pattern and number of AsORs expressed in antennae are similar in males and females. However, the relative levels of AsOR transcripts are much higher in female antennae than in male antennae, which indicates that the odor sensitivity is likely to be increased in female mosquitoes. Based on the expression patterns and previous studies, we have speculated on the functions of some OR genes but this needs to be validated by further behavioral, molecular and electrophysiological studies. Further studies are necessary to compare the olfactory-driven behaviors and identify receptors that respond strongly to components of human odors that may act in the process of human recognition.
This is the first genome-wide analysis of the entire repertoire of OR genes in An. sinensis. Characterized features and profiled expression patterns of ORs suggest their involvement in the odorous reception of this species. Our findings provide a basis for further research on the functions of OR genes and additional genetic and behavioral targets for more sustainable management of An. sinensis in the future.
嗅觉系统在调节昆虫行为方面起着至关重要的作用。气味物质的检测主要由各种嗅觉受体 (ORs) 介导，这些受体在化学感受器纤毛的嗅觉神经元的树突中表达。中华按蚊是东亚地区主要的疟疾媒介，其基因组最近已成功测序和注释。在这项研究中，我们展示了中华按蚊不同化学感受组织中 OR 基因的全基因组鉴定和表达谱分析。
使用中华按蚊的可用基因组序列鉴定 OR 基因。进行了一系列生物信息学分析，以研究 OR 基因的结构、基因组分布、选择压力和系统发育关系，OR 氨基酸序列中的保守结构域和特定功能位点。从两性触角、喙和下颚须的转录组数据中分析 OR 基因的表达水平。
共鉴定和表征了中华按蚊中的 59 个推定的 OR 基因。这个数量明显少于冈比亚按蚊。这种差异是由于两个物种分化后 OR 基因的收缩还是扩张引起的，目前尚不清楚。RNA-seq 分析表明，AsORs 具有明显的组织和性别特异性表达模式。大多数 AsORs 在触角中高表达，并且雌雄触角中表达的 AsOR 数量和表达模式相似。然而，雌性触角中 AsOR 转录物的相对水平远高于雄性触角，这表明雌性蚊子的气味敏感性可能增加。根据表达模式和先前的研究，我们推测了一些 OR 基因的功能，但这需要通过进一步的行为、分子和电生理学研究来验证。需要进一步的研究来比较嗅觉驱动的行为，并确定对人类气味成分反应强烈的受体，这些受体可能在人类识别过程中发挥作用。
这是中华按蚊全基因组范围内 OR 基因全谱分析的首次研究。OR 特征和表达模式分析表明它们参与了该物种的气味接收。我们的发现为进一步研究 OR 基因的功能以及未来更可持续地管理中华按蚊的其他遗传和行为靶标提供了基础。
