April 21, 2021
Institute for Advanced Biosciences, Keio University
Tokyo University of Agriculture and Technology
Ryutsu Keizai University
Hosei University
A research group led by Associate Professor Kazuharu Arakawa, Project Research Associate Dai Mori, and Project Lecturer Noriaki Kono of the Institute for Advanced Biosciences, Keio University; Associate Professor Takeshi Suzuki of the Graduate School of Agriculture, Tokyo University of Agriculture and Technology; Professor Tetsuo Gotoh of the Faculty of Economics, Ryutsu Keizai University; and Professor Satoshi Shimano of the Center for Natural Sciences / Faculty of Intercultural Communication, Hosei University, has identified the genes for the silk protein (fibroin) that constitutes the silk of plant-parasitic spider mites. While spider mites are major agricultural pests, they are also known as organisms that produce stiff, nanoscale silk threads that are thinner than those of silkworms and spiders. In 2011, a paper on the spider mite genome was published in the journal Nature, and multiple fibroin-like genes were predicted from its complete base sequence, but analysis at the protein level had not progressed. Using the species whose genome was sequenced and two closely related species (the Kanzawa spider mite and the citrus red mite) as materials, this research group identified two fibroin genes that constitute mite silk through comparative genomics and multi-omics analysis, combining transcriptome sequencing and silk proteomics. Surprisingly, these genes were different from any of those previously predicted. Furthermore, their amino acid composition and protein secondary structure have similarities to the equally stiff decorative silk and cocoon silk of spiders, which may partially reflect the mechanical properties of mite silk. The identification of the fibroin genes for mite silk in this study and the availability of their full-length sequences are expected to lead not only to advances in the evolutionary biology of silk spun by arthropods but also to the development of new pesticides targeting these genes and to industrial applications through the mass production of mite silk.
For the full press release, please see below.