Double strand RNA delivery system for plant-sap-feeding insects

Abstract

Double-stranded RNA (dsRNA)-mediated gene silencing, also known as RNA interference (RNAi), has been a breakthrough technology for functional genomic studies and represents a potential tool for the management of insect pests. Since the inception of RNAi numerous studies documented successful introduction of exogenously synthesized dsRNA or siRNA into an organism triggering highly efficient gene silencing through the degradation of endogenous RNA homologous to the presented siRNA. Managing hemipteran insect pests, especially Halyomorpha halys (Stål) (Heteroptera: Pentatomidae), the brown marmorated stink bug (BMSB), is critical to food productivity. BMSB was recently introduced into North America where it is both an invasive agricultural pest of high value specialty, row, and staple crops, as well as an indoor nuisance pest. RNAi technology may serve as a viable tool to manage this voracious pest, but delivery of dsRNA to piercing-sucking insects has posed a tremendous challenge. Effective and practical use of RNAi as molecular biopesticides for biocontrol of insects like BMSB in the environment requires that dsRNAs be delivered in vivo through ingestion. Therefore, the key challenge for molecular biologists in developing insect-specific molecular biopesticides is to find effective and reliable methods for practical delivery of stable dsRNAs such as through oral ingestion. Here demonstrated is a reliable delivery system of effective insect-specific dsRNAs through oral feeding through a new delivery system to induce a significant decrease in expression of targeted genes such as JHAMT and Vg. This state-of-the-art delivery method overcomes environmental delivery challenges so that RNAi is induced through insect-specific dsRNAs orally delivered to hemipteran and other insect pests.

Prospects, challenges and current status of RNAi through insect feeding

“…Targeting insects that feed internally (sap sucking and endophagous insects) with synthetic dsRNA requires a different strategy because spraying dsRNA solutionsx2 on plant surfaces is not effective against these species. A recent study used the plant vascular system to deliver dsRNA solutions via soil irrigation and trunk injection to target the sap‐sucking brown marmorated stink bug . The irrigation and trunk injection of the vitellogenin‐A1 and juvenile hormone acid O‐methyltransferase dsRNAs showed 35–40% mortality in brown marmorated stink bugs .…”

Synthetic biology approach for plant protection using dsRNA

“…Consistent with the central role of dsRNA in triggering RNAi, numerous studies have shown that plants treated with virus‐specific dsRNA or single‐stranded RNA (ssRNA) molecules that fold into hairpin conformation showed antiviral resistance (Carbonell et al ., ; Gan et al ., ; Konakalla et al ., ; Tenllado and Diaz‐Ruiz, ; Tenllado et al ., ,b; Yin et al ., ). dsRNAs were also shown to be effective against fungi (Koch et al ., ; Wang et al ., , ) and insects (Baum et al ., ; Ghosh et al ., ; Li et al ., ; Luo et al ., ), thus providing important implications for dsRNA‐triggered RNAi as an emerging novel approach for crop protection. RNAi has been deployed for plant protection since it was discovered.…”

Identification and characterization of capa and pyrokinin genes in the brown marmorated stink bug, Halyomorpha halys (Hemiptera): Gene structure, immunocytochemistry, and differential expression

“…The spread of BMSB populations is threatening a wide range of economic crops (Leskey & Nielsen, ). It has spurred to develop various management options including pheromone‐based monitoring and trapping (Khrimian et al, ), biological control utilizing entomopathogenic fungi (Gouli et al, ), and a recent RNA interference (RNAi)‐mediated approach (Ghosh, Hunter, Park, & Gundersen‐Rindal, , ).…”