Strategies for the production of dsRNA biocontrols as alternatives to chemical pesticides

Abstract

Current crop pest control strategies rely on insecticidal and fungicidal sprays, plant genetic resistance, transgenes and agricultural practices. However, many insects, plant viruses, and fungi have no current means of control or have developed resistance against traditional pesticides. dsRNA is emerging as a novel sustainable method of plant protection as an alternative to traditional chemical pesticides. The successful commercialisation of dsRNA based biocontrols for effective pest management strategies requires the economical production of large quantities of dsRNA combined with suitable delivery methods to ensure RNAi efficacy against the target pest. A number of methods exist for the production and delivery of dsRNA based biocontrols and here we review alternative methods currently employed and emerging new approaches for their production. Additionally, we highlight potential challenges that will need to be addressed prior to widespread adoption of dsRNA biocontrols as novel sustainable alternatives to traditional chemical pesticides.

New Records of Wood- and Bark-Inhabiting Nematodes from Woody Plants with a Description of Bursaphelenchus zvyagintsevi sp. n. (Aphelenchoididae: Parasitaphelenchinae) from Russia

“…Due to the prohibition or restriction of many nematicides, alternative control strategies are needed to control these diseases. Accurate nematode diagnostics, early detection of the neglected nematode pest refugia, identification of insect vectors of nematodes and suppressive bacterial and fungal agents are important for the development of effective control measures [ 1 , 2 , 3 , 4 , 5 ].…”

Utilization of Bacteriophage phi6 for the Production of High-Quality Double-Stranded RNA Molecules

“…Typically, bacterial or yeast cells are transformed with a plasmid, in which the target sequence for RNAi is inserted between two convergent T7 promoters. Alternatively, a sequence forming a hairpin upon transcription can be designed and inserted after a single T7 promoter [ 30 ].…”

Optimising the production of dsRNA biocontrols in microbial systems using multiple transcriptional terminators

“…Non-transformative methods, as defined in the review by Hough et al, (2022), are used to produce exogenous dsRNA, these include in vitro transcription (IVT), microbial expression in bacteria or fungi, and cell-free synthesis, offering rapid and controlled production of dsRNA, suitable for experimental research and scalable quantities. In contrast, transformative methods involving genetically modified (GM) plants allow continuous dsRNA production, beneficial for applications like pest-resistant crops, reducing pesticide use and enhancing yields.…”

“…However, GM crop methods raise concerns regarding gene flow, and regulatory complexities. Both methods have their advantages and limitations, with each of the production methods providing specific modes of action (Christiaens et al, 2020;Hough et al, 2022) The production of dsRNA in E. coli has predominantly used the RNase III deficient strain HT115 (DE3) (Ahn et al, 2019;Bento et al, 2020;García et al, 2015;Hull & Timmons, 2004;Meng et al, 2020;Nwokeoji et al, 2016;Ongvarrasopone et al, 2008;Posiri et al, 2013). Initial plasmid DNA constructs consisted of two opposing convergent T7 promoters, flanking the dsRNA sequence.…”

“…However, GM crop methods raise concerns regarding gene flow, and regulatory complexities. Both methods have their advantages and limitations, with each of the production methods providing specific modes of action (Christiaens et al, 2020; Hough et al, 2022)…”