Bombyx mori Vps13d is a key gene affecting silk yield

Area of Science:

• Genetics and Molecular Biology
• Insect Science
• Biochemistry

Background:

• Bombyx mori is an economically important insect, primarily valued for its silk production.
• Key genes influencing silk yield in B. mori remain largely unidentified.
• The function of Bombyx mori vacuolar protein sorting-associated protein 13d (BmVps13d) has not been previously reported.

Purpose of the Study:

• To investigate the function of BmVps13d in Bombyx mori.
• To determine the role of BmVps13d in silk yield.
• To explore the genetic basis of silk yield variation in silkworms.

Main Methods:

• Comparative sequence analysis of BmVps13d with homologous proteins in Drosophila melanogaster and Homo sapiens.
• Quantitative analysis of BmVps13d gene expression in high-silk-yield (JS) and low-silk-yield (L10) silkworm strains.
• Dual luciferase reporter assay to assess promoter activity of the BmVps13d gene.
• CRISPR/Cas9 gene editing to create BmVps13d mutations in B. mori.

Main Results:

• BmVps13d protein exhibits sequence homology with orthologs in D. melanogaster and H. sapiens.
• BmVps13d expression levels were significantly higher in the midgut and silk glands of high-yield JS silkworms compared to low-yield L10 silkworms.
• Genetic variations in the BmVps13d promoter region of L10 silkworms correlated with reduced promoter activity.
• CRISPR/Cas9-induced mutations in BmVps13d led to a 24.7% decrease in larval weight and significant reductions in silk yield (27.1% in females, 11.8% in males).

Conclusions:

• BmVps13d plays a critical role in regulating larval growth and silk production in Bombyx mori.
• Genetic variations affecting BmVps13d expression and function contribute to differences in silk yield.
• This study provides a foundation for understanding the molecular mechanisms underlying silk yield and for breeding silkworms with enhanced silk production capabilities.