RNA interference-mediated silencing of genes involved in the immune responses of the soybean pod borer Leguminivora glycinivorella (Lepidoptera: Olethreutidae)

Abstract

RNA interference (RNAi) technology may be useful for developing new crop protection strategies against the soybean pod borer (SPB; Leguminivora glycinivorella), which is a critical soybean pest in northeastern Asia. Immune-related genes have been recently identified as potential RNAi targets for controlling insects. However, little is known about these genes or mechanisms underlying their expression in the SPB. In this study, we completed a transcriptome-wide analysis of SPB immune-related genes. We identified 41 genes associated with SPB microbial recognition proteins, immune-related effectors or signalling molecules in immune response pathways (e.g., Toll and immune deficiency pathways). Eleven of these genes were selected for a double-stranded RNA artificial feeding assay. The down-regulated expression levels of LgToll-5-1a and LgPGRP-LB2a resulted in relatively high larval mortality rates and abnormal development. Our data represent a comprehensive genetic resource for immune-related SPB genes, and may contribute to the elucidation of the mechanism regulating innate immunity in Lepidoptera species. Furthermore, two immune-related SPB genes were identified as potential RNAi targets, which may be used in the development of RNAi-mediated SPB control methods.

Transcriptomic and proteomic analyses of the mechanisms of overwintering diapause in soybean pod borer (Leguminivora glycinivorella)

“…[1][2][3] Hatched larvae enter the pod and use the young beans as a food source until they develop into fourth instar larvae, causing considerable loss of yield and seed quality. [4][5][6] Insecticides have been used to control L. glycinivorella infestations over the past four decades. However, the larvae within soybean pods under a closed canopy are not exposed to the applied insecticides.…”

“…[9][10][11] Leguminivora glycinivorella is a univoltine insect and does not migrate. 4 The fourth instar (mature) larvae enter the soil in mid to late September, make a tight cocoon in which they overwinter, 1 and remain in this state for 8-9 months until temperatures are warm enough to allow pupation and adult emergence. 12,13 To survive this period, insects need to endure temperatures encountered at high latitudes (−15 to −50°C).…”

“…north‐eastern China, North Korea, Japan, and Russian Far East 1–3 . Hatched larvae enter the pod and use the young beans as a food source until they develop into fourth instar larvae, causing considerable loss of yield and seed quality 4–6 . Insecticides have been used to control L. glycinivorella infestations over the past four decades.…”

“…However, systemic insecticides have insidious effects on bee pollinators and the environment 9–11 . Leguminivora glycinivorella is a univoltine insect and does not migrate 4 . The fourth instar (mature) larvae enter the soil in mid to late September, make a tight cocoon in which they overwinter, 1 and remain in this state for 8–9 months until temperatures are warm enough to allow pupation and adult emergence 12,13 …”