The Small RNA Profile of Silkworm Hemolymph Using Deep Sequencing

Human utilization of the mulberry-silkworm interaction started at least 5,000 years ago and greatly influenced world history through the Silk Road. Complementing the silkworm genome sequence, here we describe the genome of a mulberry species (Morus notabilis C. K. Schneider). In the 330 Mb genome assembly of M. notabilis, we identified 128 Mb of repetitive sequences and 29,338 genes, 60.8% of which were supported by transcriptome sequencing. Mulberry gene sequences appear to evolve ~3 times faster than other Rosales, perhaps facilitating its spread to Europe, Africa, and America. It is among few eudicots but several Rosales not preserving genome duplications in more than 100 million years – however neopolyploid series in mulberry and several others suggest that new duplications may confer benefits. Strikingly, five predicted mulberry miRNAs were found in the hemolymph and silkglands of silkworm, suggesting profound molecular level interactions that promise to expand knowledge of plant-herbivore relationship which constitute key elements of most terrestrial habitats. In addition, we investigated the characters of hemolymph small RNA. Overall design: small mRNA profiles of silkworm hemolymph in the fifth instar day-5 silkworm were generated by deep sequencing, in twice, using Illumina Hiseq 2000.