Thebeta-1,4-N-acetylglucosaminidase 1 gene, selected by domestication and breeding, is involved in cocoon construction ofBombyx mori
Thebeta-1,4-N-acetylglucosaminidase 1 gene, selected by domestication and breeding, is involved in cocoon construction ofBombyx mori
复制标题
通过驯化和育种选择的β-1, 4-N-乙酰氨基葡萄糖苷酶1基因参与家蚕的茧构建
DOI：
10.1371/journal.pgen.1008907
复制
发表时间：
2020-07-01
期刊：
影响因子：
4.5
通讯作者：
Dai, Fangyin
中科院分区：
文献类型：
--
作者：
Li, Chunlin;Tong, Xiaoling;Dai, Fangyin
茧为许多昆虫物种的变态提供了一个受保护的空间。蚕丝蛋白是用于茧构造的纤维的前体。破译丝蛋白合成的遗传基础将提高我们对茧的构造和构造茧的物种的适应性的理解。我们使用家蚕（家蚕）作为模型，以确定影响丝蛋白合成和蚕茧结构的基因。利用数量遗传分析方法，对家蚕在驯化育种过程中筛选出的一个基因--β-1，4-N-乙酰氨基葡萄糖苷酶1（BmGlcNase 1）进行了研究，结果表明，该基因与家蚕的丝胶合成有关。基于转基因的功能验证证实BmGlcNase 1正调控蚕茧中的丝胶含量。GlcNase 1在有茧昆虫进化中的选择压力高于无茧昆虫。这表明它在结茧过程中具有保守的功能。这些结果揭示了昆虫丝蛋白合成和茧结构的遗传基础。全变态昆虫有不同的幼虫、蛹和成虫阶段。蛹阶段通常是不动的，可以受到捕食，但茧提供蛹保护许多昆虫物种。茧为蛹向成虫的变态提供了空间。它还保护蛹免受天气，捕食者和寄生虫的侵害。丝蛋白是用于蚕茧构造的丝的前体。我们用家蚕作为模式物种来鉴定影响丝蛋白合成和茧结构的基因。利用定量遗传分析方法，证明β-1，4-N-乙酰氨基葡萄糖苷酶1（BmGlcNase 1）与蚕茧主要成分--丝胶蛋白的合成有关，其表达模式与丝腺发育和茧层量变化相关，茧层量是反映蚕茧合成丝蛋白能力的指标。BmGlcNase 1的表达上调使雌蜂和雄蜂茧中的丝胶含量分别增加13.9%和22.5%，而表达下调则使雌蜂和雄蜂茧中的丝胶含量分别减少41.2%和27.3%。基因组测序结果显示BmGlcNase 1转录起始位点（TSS）上游序列变异与BmGlcNase 1和CSW的表达相关。选择压力分析表明GlcNase 1在有茧和无茧昆虫中的选择差异（ω（1）= 0.044 vs.omega（2）= 0.154）。BmGlcNase 1基因可能参与了蚕丝中丝胶蛋白的合成和家蚕的结茧过程。
Author summary The cocoon provides a protected space for the metamorphosis of many insect species. Silk protein is a precursor of the fiber used for cocoon construction. Deciphering the genetic basis underlying silk protein synthesis will improve our understanding of cocoon construction and the adaptations of species that construct cocoons. We used the silkworm (Bombyx mori) as a model to identify genes affecting silk protein synthesis and cocoon construction. Quantitative genetic analysis was used to show that beta-1,4-N-acetylglucosaminidase 1(BmGlcNase1), a gene selected during silkworm domestication and breeding, is associated with sericin synthesis. Transgenic-based functional validation confirmed thatBmGlcNase1positively regulates sericin content in the silkworm cocoon. The selective pressure ofGlcNase1in the evolution of insects with cocoons is higher than those without cocoons. This indicates that it has a conserved function in the cocooning process. These results reveal aspects of the genetic basis of silk protein synthesis and the cocoon construction of insects.Holometabolous insects have distinct larval, pupal, and adult stages. The pupal stage is typically immobile and can be subject to predation, but cocoon offers pupal protection for many insect species. The cocoon provides a space in which the pupa to adult metamorphosis occurs. It also protects the pupa from weather, predators and parasitoids. Silk protein is a precursor of the silk used in cocoon construction. We used the silkworm as a model species to identify genes affecting silk protein synthesis and cocoon construction. We used quantitative genetic analysis to demonstrate that beta-1,4-N-acetylglucosaminidase 1(BmGlcNase1) is associated with synthesis of sericin, the main composite of cocoon.BmGlcNase1has an expression pattern coupled with silk gland development and cocoon shell weight (CSW) variation, and CSW is an index of the ability to synthesize silk protein. Up-regulated expression ofBmGlcNase1increased sericin content by 13.9% and 22.5% while down-regulation reduced sericin content by 41.2% and 27.3% in the cocoons of females and males, respectively. Genomic sequencing revealed that sequence variation upstream of theBmGlcNase1transcriptional start site (TSS) is associated with the expression ofBmGlcNase1and CSW. Selective pressure analysis showed thatGlcNase1was differentially selected in insects with and without cocoons (omega(1)= 0.044 vs.omega(2)= 0.154). This indicates that this gene has a conserved function in the cocooning process of insects.BmGlcNase1appears to be involved in sericin synthesis and silkworm cocooning.