A first greenhouse application of bacteria-expressed and nanocarrier-delivered RNA pesticide for Myzus persicae control

Abstract

There are two main limitations for sprayable RNA pesticide development: delivery e ciency and synthetic cost of double-stranded RNA (dsRNA). We previously constructed a nanocarrier-based transdermal dsRNA delivery system and a novel bacteria-based hairpin RNA (hpRNA) expression system to solve these challenges. Herein, as a subsequent exploration of RNA pesticide (sprayable ds/hpRNA for pest control), we performed a greenhouse application of bacteria-expressed and nanocarrier-delivered RNA pesticide on green peach aphid. The nanoparticle SPc could combine and deliver dsRNA across the aphid cuticle, and V-type proton ATPase subunits d (ATP-d) and G (ATP-G) were selected as the potential RNA interference (RNAi) targets. Our plasmid-Escherichia coli system simultaneously expressing ATP-d and ATP-G hairpin RNAs (hpRNAs) was constructed for mass production of hpRNA. The expressed hpRNA was mixed with SPc and detergent to form RNA formulation, which showed a certain insecticidal activity through the spray application in the greenhouse. Total control e cacy of our RNA pesticide could reach 61% on 3 d, and maintained at 50% until the sixth day. To our knowledge, our study is the rst attempt to apply the bacteria-expressed and nanocarrier-delivered RNA pesticides for pest control in the greenhouse trial, which is bene cial for promoting the development of RNA pesticides. Key Message• SPc can protect and deliver dsRNA from degradation for e cient gene silencing• hpRNA is expressed in E. coli system to develop a novel RNA insecticide • Our RNA pesticide can be applied to control aphids in greenhouse • Our study brings the concept of RNAi-based pest management to practical application

Nanocarrier-Loaded Imidaclothiz Promotes Plant Uptake and Decreases Pesticide Residue

“…The dead aphids caused by various formulations exhibited dehydration and turned to black on tobacco leaves ( Figure S3 ). According to the previous studies [ 10 , 13 ], the dropping rate of aphids treated with imidaclothiz/SPc complex was significantly higher than that of imidaclothiz, and the control efficacy of imidaclothiz/SPc complex could reach 76.75% (4 d) and 81.91% (6 d) compared with 39.84% (4 d) and 47.90% (6 d) in imidaclothiz treatment ( Figure 5 A,B). National standard (grade and investigation method of tobacco diseases and insect pests, GB/T 23222-2008) was also used to analyze the control efficacy.…”

“…Two methods were used to calculate the control efficacy. (1) According to the previous studies [ 10 , 13 ], the dropping rate of insect (DRI) and control efficacy (CE) were calculated using the formulas of DRI (%) = (aphid number before pesticide application − aphid number after pesticide application) ÷ aphid number before pesticide application × 100% and CE (%) = (DRI in the treatment plot − DRI in the control plot) ÷ (100 − DRI in the control plot) × 100%. (2) According to the national standard (grade and investigation method of tobacco diseases and insect pests, GB/T 23222-2008), the plants infested with aphids were classified.…”

“…Polymeric nanomaterials have been recently applied for agrochemical delivery, and it is important to explore efficient polymer nanocarriers. A star polymer (SPc) has been designed and synthesized to deliver both double-stranded RNA (dsRNA) and synthetic/botanical pesticides [ 9 , 10 , 11 , 12 , 13 ]. The SPc can activate the clathrin-mediated endocytosis to improve the delivery efficiency of loaded cargo [ 14 , 15 ].…”

Salivary Effector Sm9723 of Grain Aphid Sitobion miscanthi Suppresses Plant Defense and Is Essential for Aphid Survival on Wheat

“…Salivary effector Bt56 in whiteflies B. tabaci was silenced by feeding with artificial diet containing dsRNA, resulting in significantly reduced whitefly performance on host plants and shorter phloem feeding durations [43]. Nanocarrier-mediated RNAi is a practical delivery system for silencing target genes of hemipteran insects, such as soybean aphid Aphis glycines and M. persicae, and is considered a promising strategy for gene function characterization and pest control [44][45][46]. In this study, to further examine the roles of Sm9723 on S. miscanthi fitness, the Sm9723 gene was silenced following application of the nanocarrier-mediated transdermal dsRNA delivery system.…”

“…These outcomes suggest Sm9723 is essential for aphid adaptability to host plants as a salivary effector. Spray application of dsRNA pesticide shows great potential in controlling M. persicae and several plant pathogens [46,47]. Further, previous studies demonstrated that host induced gene silencing (HIGS) in transgenic wheat and barley plants targeting essential genes of S. avenae can successfully confer resistance against aphids [48,49].…”