Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China; University of Chinese Academy of Sciences, 100049, Beijing, China.
College of Forestry, Shandong Agricultural University, Taian Shandong, 271018, China.
Insect Biochem Mol Biol. 2021 Dec;139:103672. doi: 10.1016/j.ibmb.2021.103672. Epub 2021 Oct 23.
The silkworm (Bombyx mori) is a domesticated and economically important insect. During the whole growth period, silkworm suffers various pathogen infection. Nearly 80% of silk cocoon crop losses are attributed to viral diseases. The circular double-stranded DNA virus Bombyx mori nuclepolyhedrovirus (BmNPV) is the major viral pathogen responsible for massive silkworm death and huge economic losses in the sericulture industry. Up to now, almost all the new strategies for developing immunity against BmNPV are in laboratory strains because of the lack of transgenic technology in industrial silkworm strains. We previously demonstrated that modification of BmNPV genome DNA with the antivirus transgenic CRISPR/Cas9 system effectively improved the resistance of laboratory silkworm strains to viral pathogens. The industrial strains are monovoltine or bivoltine. It is very difficult to break the diapause before microinjection for genetic transformation. Here, we show that the anti-BmNPV transgenic CRISPR/Cas9 system also works in the industrial silkworm strain Jingsong. In this study, we successfully broke diapause and obtained generation-skipping embryos and constructed two TG Jingsong lines. Both lines exhibited significantly enhanced immunity to BmNPV without significant changes in most of the commercially important traits. These results demonstrate that the construction of TG silkworm lines carrying a heritable immune defense system against BmNPV could be an effective strategy to enhance the resistance of industrial silkworm strains to the most devastating DNA virus. The research opened a window for genetic modification of the important strains from laboratory strains to industrial strains.
家蚕（Bombyx mori）是一种经过驯化且经济重要的昆虫。在整个生长期间，家蚕会遭受各种病原体感染。近 80%的蚕茧作物损失归因于病毒性疾病。圆双链 DNA 病毒家蚕核多角体病毒（BmNPV）是导致养蚕业大量家蚕死亡和巨大经济损失的主要病毒病原体。到目前为止，由于工业家蚕品系中缺乏转基因技术，几乎所有开发针对 BmNPV 免疫的新策略都在实验室品系中进行。我们之前证明，使用抗病毒转基因 CRISPR/Cas9 系统修饰 BmNPV 基因组 DNA 可有效提高实验室家蚕品系对病毒病原体的抗性。工业品系为一化性或二化性。在微注射进行遗传转化之前，打破滞育非常困难。在这里，我们表明抗 BmNPV 的转基因 CRISPR/Cas9 系统在家蚕品系 Jingsong 中也有效。在这项研究中，我们成功打破了滞育并获得了代跳胚胎，并构建了两个 TG Jingsong 品系。这两个品系对 BmNPV 的免疫力显著增强，而大多数商业上重要的性状没有明显变化。这些结果表明，构建携带针对 BmNPV 的可遗传免疫防御系统的 TG 家蚕系可能是增强工业家蚕品系对最具破坏性的 DNA 病毒抗性的有效策略。这项研究为从实验室品系到工业品系的重要品系的遗传修饰开辟了一扇窗户。
