BmSd gene regulates the silkworm wing size by affecting the Hippo pathway

Abstract

Insect wings are developed from the wing disc during metamorphosis. Bombyx mori, a model lepidopteran insect, loses flight ability after long-term domestication from the wild silkworm, Bombyx mandarina. The mw mutant (u11 strain) shows minute wings compared to wild type (e.g., p50 strain) wings. RNA sequencing analysis previously revealed differential Hippo-pathway-related gene expression between the u11 and p50 strains. The Hippo pathway is an evolutionarily conserved signaling cascade that controls organ size during development in animals. In this study, the function of BmSd which has been characterized as one of the Hippo-pathway-related genes was analyzed for silkworm wing development. We found that mats, warts, and hippo expression levels were higher in u11 compared to p50 wing discs. BmSd (scalloped) expression, which encodes a prominent transcriptional partner to Yorkie (Yki), gradually decreased during the wandering stage in u11, but exhibited the opposite expression pattern in p50. When BmSd was knocked down by small interfering RNA during the wandering stage in the p50 strain, 57.9% of the individuals showed minute wings. Additionally, ex, kibra, and wingless expression levels decreased in the BmSd knockdown mutant. Further, BmSd deletion mediated by clustered regularly interspaced short palindromic repeats (CRISPR) / CRISPR-associated protein 9 induced 50% of individuals with minute wings, a phenotype similar to the mw mutant. This result demonstrates that BmSd plays pivotal roles in silkworm wing development. Our results show that the Hippo signaling pathway participates and plays crucial roles in the regulation of silkworm wing development, and our findings provide a basis for further research on B. mori wing development.

Characterization and analysis of full-length transcriptomes from two grasshoppers, Gomphocerus licenti and Mongolotettix japonicus

“…The KEGG analysis showed that 209 and 211 KEGG pathways were successfully annotated in G. licenti and M. japonicus, respectively. And among which Wnt, Notch, Hedgehog, Hippo and other pathways played critical roles in insect growth and development, for example, the Wnt signaling pathway has been shown to be essential for both embryogenesis and organogenesis, such as controlling axis elongation and leg development of one short-germ insect 63 , and the Hippo signaling pathway is an evolutionally-conserved signaling cascade that plays a role in controlling organ size during animal development, such as controlling the size of silkworm wings 64 . GO annotations are classified into three main categories: biological process, cellular component and molecular function.…”

Bmcas‐1 plays an important role in response against BmNPV infection in vitro

“…To improve the RNAi effect, two specific small interfering RNAs (siRNAs) targeting different Bmcas‐1 domains were designed following the previously reported method (Yin et al, 2019). The siRNA oligos used to synthesize siRNA were synthesized by SUNYA Biotechnology (Table 2).…”

Bmapaf-1 is Involved in the Response against BmNPV Infection by the Mitochondrial Apoptosis Pathway

“…To knockdown the expression of Bmapaf-1 in BmN cells, two specific siRNAs targeting sequences located in the functional domain of Bmapaf-1 were selected and designed using the method in a previous study [ 23 ]. The target DNA sequence was inserted behind the T7 promoter, and the siRNA oligos were synthesized by SUNYA Biotechnology (Zhejiang, China; Table 2 ).…”