Yin Ling, Wang Kang, Niu Lin, Zhang Huanxin, Chen Yuyong, Ji Ting, Chen Guohong
Jiangsu Agri-animal Husbandry Vocational College, Taizhou, China.
College of Animal Science and Technology, Yangzhou University, Yangzhou, China.
Front Genet. 2018 Oct 24;9:416. doi: 10.3389/fgene.2018.00416. eCollection 2018.
The reproductive division of labor, based on caste differentiation in social insects, is of great significance in evolution. Generally, a healthy bee colony consists of a queen and numerous workers and drones. Despite being genetically identical, the queen and workers exhibit striking differences in morphology, behavior, and lifespan. The fertilized eggs and larvae selectively develop into queen and worker bees depending on the local nutrition and environment. Bee worker larvae that are transplanted within 3 days of age to queen cells of a bee colony can develop into queens with mature ovaries. This phenomenon is important to understand the regulatory mechanisms of caste differentiation. In this study, we transplanted worker larvae () at the age of 1 (L1), 2 (L2), and 3 days (L3) into queen cells until the age of 4 days. Subsequently, genetic changes in these larvae were evaluated. The results revealed that the number of differentially expressed genes (DEGs) in L1 vs. L3 was more than that in L1 vs. L2. Furthermore, many of the genes that were downregulated are mostly involved in metabolism, body development, reproductive ability, and longevity, indicating that these functions decreased with the age of transplantation of the larvae. Moreover, these functions may be critical for worker larvae to undergo the developmental path to become queens. We also found that the DEGs of L1 vs. L2 and L1 vs. L3 were enriched in the MAPK, FoxO, mTOR, Wnt, TGF-beta Hedgehog Toll and Imd, and Hippo signaling pathways. Gene ontology analysis indicated that some genes are simultaneously involved in different biological pathways; through these genes, the pathways formed a mutual regulatory network. Casein kinase 1 (CK 1) was predicted to participate in the FoxO, Wnt, Hedgehog, and Hippo signaling pathways. The results suggest that these pathways cross talked through the network to modify the development of larvae and that CK 1 is an important liaison. The results provide valuable information regarding the regulatory mechanism of environmental factors affecting queen development, thus, amplifying the understanding of caste differentiation in bees.
基于社会性昆虫种型分化的生殖分工在进化过程中具有重要意义。一般来说，一个健康的蜂群由一只蜂王以及众多工蜂和雄蜂组成。尽管蜂王和工蜂基因相同，但它们在形态、行为和寿命方面表现出显著差异。受精卵和幼虫会根据当地营养和环境选择性地发育成蜂王和工蜂。在3日龄内被移植到蜂群王台中的蜜蜂工蜂幼虫能够发育成具有成熟卵巢的蜂王。这一现象对于理解种型分化的调控机制至关重要。在本研究中，我们将1日龄（L1）、2日龄（L2）和3日龄（L3）的工蜂幼虫移植到王台中直至4日龄。随后，对这些幼虫的基因变化进行了评估。结果显示，L1与L3之间差异表达基因（DEG）的数量多于L1与L2之间的差异表达基因数量。此外，许多下调的基因大多参与代谢、身体发育、生殖能力和寿命相关过程，这表明这些功能随着幼虫移植年龄的增长而下降。而且，这些功能可能对于工蜂幼虫走上发育成蜂王的路径至关重要。我们还发现，L1与L2以及L1与L3之间的差异表达基因在丝裂原活化蛋白激酶（MAPK）、叉头框蛋白O（FoxO）、哺乳动物雷帕霉素靶蛋白（mTOR）、Wnt、转化生长因子β（TGF - beta）、刺猬信号通路（Hedgehog）、Toll和免疫缺陷（Imd）以及河马信号通路（Hippo）中富集。基因本体分析表明，一些基因同时参与不同的生物学途径；通过这些基因，这些途径形成了一个相互调控的网络。酪蛋白激酶1（CK 1）被预测参与FoxO信号通路、Wnt信号通路、刺猬信号通路和河马信号通路。结果表明，这些信号通路通过该网络相互作用，从而改变幼虫的发育，并且CK 1是一个重要的联络因子。这些结果为影响蜂王发育的环境因素调控机制提供了有价值的信息，从而加深了对蜜蜂种型分化的理解。
