Transcriptome and proteomics-based analysis to investigate the regulatory mechanism of silk gland differences between reciprocal cross silkworm, Bombyx mori

Abstract

• The heterosis of the orthogonal group was higher than that of reverse cross group. • Proteomics and transcriptomics analysis of the reciprocal cross silkworm. • Six DEGs and DEPs between the reciprocal cross silkworms were validated by qRT-PCR. • Serpin-32 expression may cause silk gland difference between reciprocal silkworms. The silkworm, Bombyx mori , is an important model economic insect. Cross breeding is an important way to select excellent silkworm varieties, and different combinations among the same parents often show different genetic characters. To explore the regulatory mechanism of silk gland differences in reciprocal cross silkworm, the 3rd day of the 5th instar of the orthogonal silkworm (306♀ × NB♂, 798♀ × NB♂) and the reverse cross silkworm (NB♀ × 306♂, NB♀ × 798♂) silk glands were used as experimental materials, then using Label-free-based proteomics and RNA-Seq-based transcriptomics for analysis. Besides, the qRT-PCR was used to validate the expression of differentially expressed genes. The results showed that in NB♀ × 306♂ VS 306♀ × NB♂ group, 280 differentially expressed genes and 238 differential proteins were up-regulated while 40 differentially expressed genes and 149 differential proteins were down-regulated; in NB♀ × 798♂ VS 798♀ × NB♂, 82 differentially expressed genes and 325 differential proteins were up-regulated while 113 differentially expressed genes and 258 differential proteins were down-regulated. Further analysis indicated that the up-regulation of mitochondrial aldehyde dehydrogenase gene and cytochrome P450 gene, which are related to mitochondria, might be regulated by maternal inheritance. The GO and KEGG enrichment initially showed that the differential genes and proteins are mainly involved in processes such as protease metabolism, ATP hydrolysis, lipid transport, insect hormone synthesis, and TCA cycle. The down-regulated expression of ecdysone oxidase and Serpin-32 in the reverse cross group will reduce the energy utilization in the process of silk gland synthesis, increase the hydrolysis of serine, affect the synthesis and transport of silk protein, and cause the difference between reciprocal crosses.