Guo Yueqin, Zhang Qi, Hu Xiao, Pang Chunxiu, Li Jilian, Huang Jiaxing
Key Laboratory for Insect-Pollinator Biology of the Ministry of Agriculture and Rural Affairs, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China.
College of Animal Science, Shanxi Agricultural University, Taigu, China.
Front Genet. 2021 Nov 26;12:795669. doi: 10.3389/fgene.2021.795669. eCollection 2021.
Bumblebee queens have remarkable spermathecae that store sperm for year-round reproduction. The spermathecal gland is regarded as a secretory organ that could benefit sperm storage. Queen mating provokes substantial physiological, behavioral, and gene expression changes. Here, the transcriptomes of spermathecae were compared between virgins and mated queens of the bumblebee, L., at 24 h post mating. Differentially expressed genes were further validated by real time quantitative PCR and immunofluorescence assay. In total, the expression of 11, 069 and 10, 862 genes were identified in virgins and mated queens, respectively. We identified that 176 differentially expressed genes between virgin and mated queen spermathecae: 110 (62.5%) genes were upregulated, and 66 (37.5%) genes were downregulated in mated queens. Most of the differentially expressed genes validated by RT-qPCR were concentrated on immune response [i.e., leucine-rich repeat-containing protein 70 (35.8-fold), phenoloxidase 2 (41.9-fold), and defensin (4.9-fold)] and sperm storage [i.e., chymotrypsin inhibitor (6.2-fold), trehalose transporter Tret1 (1.7-, 1.9-, 2.4-, and 2.4-fold), and heterogeneous nuclear ribonucleoprotein A3 (1.2-, and 2.6-fold)] functions in the spermathecae of mated queens. Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 (PLOD1) was hypothesized to promote the mating behavior according to RT-qPCR and immunofluorescence assay. The expression levels of most upregulated immune genes were decreased significantly at 3 days post mating. In conclusion, the external sperm transfer into spermathecae led to the significantly upregulated immune response genes in bumblebees. These gene expression differences in queen spermathecae contribute to understanding the bumblebee post mating regulatory network.
熊蜂蜂后拥有非凡的受精囊，可储存精子用于全年繁殖。受精囊腺被视为一种可能有益于精子储存的分泌器官。蜂后交配会引发大量生理、行为和基因表达的变化。在此，对交配24小时后的未交配熊蜂蜂后和已交配熊蜂蜂后L.的受精囊转录组进行了比较。通过实时定量PCR和免疫荧光测定进一步验证了差异表达基因。总共在未交配蜂后和已交配蜂后中分别鉴定出11,069个和10,862个基因的表达。我们鉴定出未交配蜂后和已交配蜂后受精囊之间有176个差异表达基因：已交配蜂后中有110个（62.5%）基因上调，66个（37.5%）基因下调。经RT-qPCR验证的大多数差异表达基因集中在免疫反应[即富含亮氨酸重复序列蛋白70（35.8倍）、酚氧化酶2（41.9倍）和防御素（4.9倍）]和精子储存[即胰凝乳蛋白酶抑制剂（6.2倍）、海藻糖转运蛋白Tret1（1.7、1.9、2.4和2.4倍）以及不均一核核糖核蛋白A3（1.2和2.6倍）]功能上，存在于已交配蜂后的受精囊中。根据RT-qPCR和免疫荧光测定，推测原胶原赖氨酸2-氧戊二酸5-双加氧酶1（PLOD1）促进交配行为。大多数上调的免疫基因在交配后3天表达水平显著下降。总之，精子外部转移到受精囊中导致熊蜂免疫反应基因显著上调。蜂后受精囊中这些基因表达差异有助于理解熊蜂交配后的调控网络。
