Enhanced silk yield in transgenic silkworm (Bombyx mori) via ectopic expression ofBmGT1-Lin the posterior silk gland

摘要

The silkworm is an economically important insect producing plentiful silk fibre in the silk gland. In this study, we reported a cross-talk between the fat body, silk gland and midgut through a glycine-serine biosynthetic pathway in the silkworm. Amino acid sequence and functional domains of glycine transporter geneBmGT1-Lwere mapped. Our results indicated thatBmGT1-Lwas specifically expressed in the midgut microvilli and persistently expressed during the feeding stages. RNA interference ofBmGT1-Lactivated glycine biosynthesis, andBmGT1-Loverexpression facilitated serine biosynthesis in the BmN4-SID1 cell. In addition, silkworms afterFibHgene knock-out or silk gland extirpation showed markedly decreasedBmGT1-Ltranscripts in the midgut and disturbed glycine-serine biosynthesis as silk yield decreased. Finally,BmGT1-Lectopic expression in the posterior silk gland promoted glycine biosynthesis, and enhanced silk yield via increasing fibroin synthesis. These results suggested that cross-talk between tissues can be used for enhancing silk yield in the silkworm.