Screening of Economically Sustainable Strains of Bivoltine Silkworm, Bombyx mori L. by Assessing the Comparative Fibroin Gene Expression

Abstract

The silkworm Bombyx mori produces natural proteins known as silk fibroin filaments, which are encased in the sericin polymers found in the silk thread used in the cocoon. The exceptional quality of bivoltine silk produced in Jammu and Kashmir is the source of reliance for sericulture farmers. The present study is the first study to investigate the genetic superiority among different bivoltine silkworm Bombyx mori L. strains, viz. M-43, SK-6, SK-7, Sanish-8, CSR-27 and BHR-3, at molecular level based on their fibroin gene expression and has been studied to ascertain fibroin synthesizing potential and to study correlation of expression analysis with economic parameters. A maximum larval weight was recorded in M-43 and minimum in CSR-27 strains of silkworm. The cocoon reeling parameters also showed significant variations in different strains of silkworm with strain M-43 recording maximum average filament length and raw silk percentage. The molecular characterization of the silkworm strains was evaluated following standard protocols to estimate the fibrion gene expression and protein profiling of the silk gland. Silkworm strain M-43 showed maximum fibrion gene expression followed by BHR-3. RT expression, heavy chain and light chain as well as the protein expression showed positive correlation with all the rearing parameters of silkworm under study except denier showed negative correlation. Among the six silkworm strains, M-43 and BHR₃ showed better results in molecular expression and economic parameters, hence can be utilized in future breeding programmes to develop fibroin-rich strains for better silk productivity and can also help us to establish silkworm gene bank for promoting sustainable sericulture worldwide.