RNA interference‐mediated silencing of vATPase subunits A and E affect survival and development of the 28‐spotted ladybeetle, Henosepilachna vigintioctopunctata

Abstract

RNA interference (RNAi) has emerged as a powerful tool for developing novel management strategies for controlling insect pests. The 28‐spotted ladybeetle, Henosepilachna vigintioctopunctata is one of the most important pests attacking solanaceous plants in Asia. In this study, the potential of dietary RNAi to manage H. vigintioctopunctata was investigated using both in vitro synthesized and bacterially expressed double‐stranded RNAs (dsRNAs) of HvvATPase A and HvvATPase E. The expression levels of HvvATPase A and HvvATPase E were higher in Malpighian tubules than in other tissue types. The silencing of HvvATPase A and HvvATPase E led to significant mortality in H. vigintioctopunctata larvae. In addition, the ingestion of HvvATPase A and HvvATPase E significantly deterred feeding behavior and subsequently arrested the development of H. vigintioctopunctata. Notably, the bacterially expressed dsRNAs consistently caused higher mortality in larvae and adults. Finally, the nontarget effects of the dsRNAs of H. vigintioctopunctata on the predatory ladybeetle Propylaea japonica were evaluated. P. japonica 1st instar larvae were administered vATPase A and vATPase E dsRNAs from H. vigintioctopunctata and P. japonica under the worst‐case scenario, in which dsGFP served as negative control. There were significant effects of dsHvvATPase A on P. japonica at the transcriptional level but not at the organismal level, whereas dsHvvATPase E did not effect P. japonica at either the transcriptional or the organismal level. Collectively, the results of the study suggest that HvvATPase A and HvvATPase E can act as novel molecular targets for the control of H. vigintioctopunctata.

Highly Variable Dietary RNAi Sensitivity Among Coleoptera

“… Lü et al (2020b ) observed approximately 60% mortality (8 days, target gene Snf7 ) and 70–85% mortality (10 days, targeting eight different coatomer components) via feeding on leaves treated with dsRNA at a concentration of 0.005 μg dsRNA/μl. Guo et al (2021) observed nearly complete mortality after 7 days (target gene vATPase E ) of feeding on leaves treated with dsRNA at a concentration of 0.01 μg dsRNA/μl. These studies by Lü et al (2020a , b , 2021a , b) and Guo et al (2021) additionally examined dietary RNAi efficacy in H. vigintioctopunctata first- and third-instar larvae and adults, using bacterially expressed dsRNA and demonstrated higher and faster RNAi efficacy in larvae compared to adults.…”

“… Guo et al (2021) observed nearly complete mortality after 7 days (target gene vATPase E ) of feeding on leaves treated with dsRNA at a concentration of 0.01 μg dsRNA/μl. These studies by Lü et al (2020a , b , 2021a , b) and Guo et al (2021) additionally examined dietary RNAi efficacy in H. vigintioctopunctata first- and third-instar larvae and adults, using bacterially expressed dsRNA and demonstrated higher and faster RNAi efficacy in larvae compared to adults. Finally, Ren et al (2021) observed significant growth retardation in H. vigintioctopunctata via consumption of transgenic potato plants.…”

“…Furthermore, the concentration of dsRNA in the diet provided to coccinellids during the abovementioned study (4 μg dsRNA/μl) was rather high in relation to what would be realistically applicable in RNAi-based plant protection, suggesting the need to re-evaluate the dietary RNAi susceptibility of some of these more RNAi-sensitive species, using more economically feasible dsRNA concentrations. Lü et al (2020aLü et al ( ,b, 2021a and Guo et al (2021) examined RNAi efficacy via oral delivery of dsRNAs targeting various genes in the 28-spotted potato ladybird (H. vigintioctopunctata). Lü et al (2020b) observed approximately 60% mortality (8 days, target gene Snf7) and 70-85% mortality (10 days, targeting eight different coatomer components) via feeding on leaves treated with dsRNA at a concentration of 0.005 μg dsRNA/μl.…”

“… Lü et al (2020a , b , 2021a , b) and Guo et al (2021) examined RNAi efficacy via oral delivery of dsRNAs targeting various genes in the 28-spotted potato ladybird ( H. vigintioctopunctata ). Lü et al (2020b ) observed approximately 60% mortality (8 days, target gene Snf7 ) and 70–85% mortality (10 days, targeting eight different coatomer components) via feeding on leaves treated with dsRNA at a concentration of 0.005 μg dsRNA/μl.…”

Vacuolar ATPase subunit F is critical for larval survival in Henosepilachna vigintioctopunctata

“…In L. decemlineata , ingestion of ds vATPaseA , ds vATPaseB or ds vATPaseE significantly increases larval mortality (Baum et al, 2007; Fu et al, 2014; Zhu et al, 2011). Similarly, introduction of either dsRNAs targeting V1 encoding genes (ds vATPaseA , ds vATPaseB , ds vATPaseC , ds vATPaseE and ds vATPaseH ), or those targeting V0 encoding genes (ds vATPasea and ds vATPased ) in H. vigintioctopunctata causes larval death (Guo et al, 2021; Lü, Guo, et al, 2020; Zeng et al, 2021a, 2021b). Feeding on ds vATPaseE in Tribolium castaneum (Whyard et al, 2009) and on ds vATPaseA in Aethina tumida (Powell et al, 2017) by larvae affects development.…”