家蚕β-1, 4-N-乙酰葡萄糖胺糖苷酶1基因（BmGlcNase1） 调控茧丝产量的分子机制研究

茧丝产量是家蚕最受关注的经济性状，培育综合优良的高产品种是推动蚕丝产业升级的基础，尤其在工厂化、智能化养殖方式到来的时代具有迫切的现实需求。然而，传统育种对茧丝产量的提升已进入了平台期，其进一步突破在很大程度上寄希望于分子育种。茧丝产量为多基因支配，其控制基因的鉴定相对较难，至今鲜有报道。申请人前期通过分子定位主体策略，鉴定到β-1,4-N-乙酰葡萄糖胺糖苷酶1（BmGlcNase1）为茧丝产量控制位点候选基因，其表达变化显著影响茧丝产量的高低。该基因功能注释为水解β-1,4-糖苷键，参与N-己糖胺水平调节。本项目着力于阐释BmGlcNase1调控茧丝产量的分子机制，并探索N-己糖胺糖苷化的相关基因在丝腺发育等过程中的功能，揭示其在家蚕分子改良中的应用价值。项目的实施将促进对茧丝产量遗传调控及相关生物学问题的理解，并为家蚕分子育种提供理论参考。

Silk production is the economic trait with great importance in sericulture. The comprehensive excellent breeds with higher silk production is the basis to upgrade this industry. And there is a larger demand of silkworm breeds with higher silk production at the coming era of industrialized and intelligent breeding. However, the improvement of silk production by traditional breeding methods has stepped into the platform for a long time. The further breakthrough on silk production improvement relies on molecular breeding to a large extent. Silk production related traits are the typical quantitative traits, controlled by multiple genes and the identification of genes underlying these traits has been proved to be challenge, which was rarely reported by now. Through genetic mapping and gene expression research, I, the applicant, identified that β-1,4-N-acetylglucosaminoglycosidase 1 (BmGlcNase1) is the candidate gene in locus controlling cocoon shell weight, an important index of silk production. Change of its expression level has a significant effect on this trait. Functional annotation showed that it is able to hydrolyze the β-1,4-glycoside bond and has the ability to regulate the N-hexosamine level. This project put efforts to elucidate the regulation mechanism of this gene on silk production, to research the new functions of genes related with N- glycosidylation in silk gland development and other processes in silkworm and to uncover their value in the molecular breeding of silkworm. Implementation of the project will advance our understanding on the genetic basis of silk production and the related biology issues, and will serve the reference for molecular breeding in silkworm.