Ren Lipin, Jocelin Ngando Fernand, Yang Fengqin, Zhang Xiangyan, Shang Yanjie, Feng Yakai, Chen Shan, Zhan Wei, Yang Xiaohong, Li Wei, Song Jiasheng, Tang Haojie, Wang Yequan, Wang Yong, Zhang Changquan, Guo Yadong
Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.
School of Forensic Medicine, Jining Medical University, Jining, Shandong, China.
BMC Genomics. 2025 May 3;26(1):442. doi: 10.1186/s12864-025-11645-3.
The oriental latrine fly, Chrysomya megacephala (Diptera: Calliphoridae), is a medically important synanthropic blow fly species characterized by its necrophagy and coprophagy, often observed near carrion and animal feces. Notably, C. megacephala always arrives at carcass earlier than other species. To elucidate the underlying mechanisms behind the host choice in C. megacephala, we present the chromosome-scale genome assembly for this species. The genome size is 816.79 Mb, with a contig N50 of 1.60 Mb. The Hi-C data were anchored to six chromosomes, accounting for 99.93% of the draft assembled genome. Comparative genomic analysis revealed significant expansions in pathways of ligand-gated ion channel activity, passive transmembrane transporter activity, and protein methyltransferase activity, which may be closely associated with host localization and oviposition. After identifying 69 odor-binding proteins (OBPs) in the assembled genome, phylogenetic analysis showed that DmelOBP99b and CmegOBP99b exhibited high homology. Transcriptome analysis demonstrated that the relative expression of CmegOBP99b was consistently the highest during the metamorphosis, and RT-qPCR further confirmed the similar results. Additionally, CmegOBP99b exhibited a strong binding affinity to DMDS (dimethyl disulfide) as determined by molecular docking. To determine the protein expression level of CmegOBP99b in various body parts, we prepared recombinant CmegOBP99b protein and anti-CmegOBP99b polyclonal antibodies. Western blot analysis showed that CmegOBP99b was significantly expressed in the female's head compared to other parts, which is consistent with RT-qPCR results. Therefore, CmegOBP99b may be the primary odor-binding protein responsible for olfactory recognition and the behavioral coordination of C. megacephala. This study not only provides valuable insights into the molecular mechanisms of oviposition localization in C. megacephala but also facilitates further research into the genetic diversity and phylogeny of the Calliphoridae family.
东方厕蝇，大头金蝇（双翅目：丽蝇科），是一种具有重要医学意义的共栖性丽蝇，以其食尸性和食粪性为特征，常在腐肉和动物粪便附近被观察到。值得注意的是，大头金蝇总是比其他物种更早到达尸体。为了阐明大头金蝇宿主选择背后的潜在机制，我们展示了该物种的染色体级基因组组装。基因组大小为816.79 Mb，重叠群N50为1.60 Mb。Hi-C数据被锚定到六条染色体上，占组装基因组草图的99.93%。比较基因组分析显示，配体门控离子通道活性、被动跨膜转运蛋白活性和蛋白质甲基转移酶活性途径有显著扩展，这可能与宿主定位和产卵密切相关。在组装基因组中鉴定出69种气味结合蛋白（OBP）后，系统发育分析表明，黑腹果蝇OBP99b和大头金蝇OBP99b表现出高度同源性。转录组分析表明，大头金蝇OBP99b在变态过程中的相对表达始终最高，RT-qPCR进一步证实了类似结果。此外，通过分子对接确定，大头金蝇OBP99b对二甲基二硫醚（DMDS）表现出强烈的结合亲和力。为了确定大头金蝇OBP99b在身体各个部位的蛋白质表达水平，我们制备了重组大头金蝇OBP99b蛋白和抗大头金蝇OBP99b多克隆抗体。蛋白质免疫印迹分析表明，与其他部位相比，大头金蝇OBP99b在雌性头部显著表达，这与RT-qPCR结果一致。因此，大头金蝇OBP99b可能是负责大头金蝇嗅觉识别和行为协调的主要气味结合蛋白。本研究不仅为大头金蝇产卵定位的分子机制提供了有价值的见解，也为丽蝇科的遗传多样性和系统发育的进一步研究提供了便利。
