Table2_Transcriptome analysis of megalurothrips usitatus (Bagnall) identifies olfactory genes with ligands binding characteristics of MusiOBP1 and MusiCSP1.DOCX

The olfactory system is an important component of insect behavior and is vital for survival and reproduction. However, the genomic characterization and molecular basis of the olfactory response of Megalurothrips usitatus remain relatively unknown. RNA sequencing-built developmental transcriptomes of nymphs, pupae, and adult M. usitatus were examined in order to establish the sequence-based background of M. usitatus olfactory responses. A total of 56,669 unigenes were annotated using GO, NR, Pfam, eggNOG, SwissProt, and KEGG. The number of differentially expressed genes between pupae and nymphs, males and nymphs, and females and nymphs were 10,498, 9,235, and 10,964, respectively. One odorant-binding protein (MusiOBP1) and one chemosensory protein (MusiCSP1) were selected from the transcriptome, and their full-length sequences were obtained using RACE PCR. The relative expression of MusiOBP1 was the highest in primordial females, whereas the relative expression of MusiCSP1 was the highest in primordial pupae. The strongest binding ability to the odor-binding protein MusiOBP1 was observed for β-citronellol. 3-Hydroxy-2-methyl-4-pyrone showed the strongest binding affinity to MusiCSP1. Our analysis suggests that MusiOBP1 and MusiCSP1 may play significant roles in mediating M. usitatus host recognition. This research will improve our knowledge of odorant-binding proteins and chemosensory proteins, which will in turn improve our understanding of insect olfactory systems.

嗅觉系统是昆虫行为的核心组成部分，对昆虫的生存与繁衍至关重要。然而，目前关于亮蓟马（Megalurothrips usitatus）的基因组特征解析及其嗅觉响应的分子基础，相关研究仍相对匮乏。本研究通过对亮蓟马若虫、蛹及成虫的发育阶段转录组开展RNA测序分析，旨在构建该物种嗅觉响应的序列研究基础。经基因注释，共获得56669条非冗余基因（unigene），注释数据库涵盖基因本体论（Gene Ontology, GO）、非冗余蛋白数据库（Non-Redundant Protein Sequence Database, NR）、蛋白质家族数据库（Protein Family, Pfam）、进化基因谱非分级注释数据库（evolutionary genealogy of genes: Non-supervised Orthologous Groups, eggNOG）、瑞士蛋白数据库（SwissProt）及京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）。蛹与若虫、雄成虫与若虫、雌成虫与若虫之间的差异表达基因数量分别为10498、9235及10964。本研究从该转录组中筛选得到1个气味结合蛋白（odorant-binding protein, OBP）MusiOBP1与1个化学感受蛋白（chemosensory protein, CSP）MusiCSP1，并通过快速扩增cDNA末端聚合酶链式反应（RACE PCR）获得了二者的全长序列。其中，MusiOBP1在初羽化雌成虫中的相对表达量最高，而MusiCSP1在早期蛹中的相对表达量最高。β-香茅醇（β-citronellol）与MusiOBP1的结合能力最强；3-羟基-2-甲基-4-吡喃酮（3-Hydroxy-2-methyl-4-pyrone）与MusiCSP1的结合亲和力最高。本研究分析表明，MusiOBP1与MusiCSP1可能在介导亮蓟马寄主识别过程中发挥关键作用。本研究将加深学界对气味结合蛋白与化学感受蛋白的认知，进而推动对昆虫嗅觉系统的深入理解。