The Gene Silencing That Became a Pesticide
RNA interference is a natural cellular mechanism present in most eukaryotic organisms that uses small double-stranded RNA molecules to silence specific genes by triggering the degradation of the messenger RNA that carries the gene's instructions to the cell's protein synthesis machinery. The mechanism was discovered in organisms including plants and insects as a defence against viral infection, where viral double-stranded RNA triggers the RNAi pathway to degrade viral genetic material before it can direct the cell to produce virus particles. The commercial application of RNAi to crop protection uses the sequence specificity of the RNAi mechanism, whose double-stranded RNA molecule triggers the silencing of only the gene whose sequence matches its own, to design pest control agents that silence essential genes in target pest organisms while leaving non-target organisms whose genes differ in sequence unaffected. A double-stranded RNA molecule designed to silence an essential gene in the Western corn rootworm, whose sequence differs from any gene in honeybees, monarch butterflies, or other non-target organisms, creates a pest control agent whose specificity in theory eliminates the off-target toxicity that has characterised broad-spectrum conventional insecticides and created the regulatory pressure that is reducing the crop protection chemical tools available to farmers globally.
The commercial development of RNAi crop protection has followed two distinct routes whose different delivery mechanisms and regulatory pathways create different commercial timelines and market opportunities. The transgenic RNAi route, in which the crop plant is genetically modified to produce the double-stranded RNA in its own cells, has been commercialised by Monsanto's (now Bayer's) SmartStax Pro corn trait, which produces a dsRNA in corn plant tissue that silences an essential gene in Western corn rootworm larvae that feed on corn roots. SmartStax Pro's EPA registration in 2017 made it the first RNAi-based crop protection product to receive regulatory approval for commercial use, and its commercial deployment in US corn production has provided the field-scale performance data that validates RNAi as a crop protection mechanism under commercial farming conditions. The spray-applied RNAi route, in which double-stranded RNA is formulated as a spray that is applied to crop foliage and ingested by the pest during feeding, does not require genetic modification of the crop and is regulated as a biopesticide rather than as a GM crop, creating a different regulatory pathway whose shorter timeline and simpler public acceptance profile may allow spray-applied RNAi to reach commercial markets in more jurisdictions and in more crop systems than transgenic RNAi.
GreenLight Biosciences and the Spray RNAi Platform
GreenLight Biosciences developed the commercial spray-applied RNAi platform whose regulatory strategy pursued EPA biopesticide registration for its Colorado potato beetle control product, a dsRNA spray that silences an essential gene in Colorado potato beetles feeding on treated foliage. The commercial development of GreenLight's spray RNAi platform demonstrated the manufacturing scale-up challenge that RNA-based agricultural products face: RNA is a complex molecule whose manufacturing cost per gram substantially exceeds that of conventional synthetic chemical pesticides, and whose stability in the outdoor environment is limited by the RNA-degrading enzymes present in soil and on plant surfaces. GreenLight's manufacturing cost reduction programme, whose cell-free RNA synthesis approach was designed to produce dsRNA at costs below the enzymatic RNA synthesis used in pharmaceutical RNA manufacturing, was the commercial feasibility condition that spray-applied RNAi crop protection required to compete economically with conventional insecticides in the commodity crop protection market.
Bayer's RNAi crop protection programme, which combines its SmartStax Pro transgenic RNAi corn trait with research into additional RNAi traits for other pest targets and crops, represents the major agrichemical company investment in RNAi as a platform technology whose long-term role in the crop protection portfolio may expand as the manufacturing cost of RNA-based active ingredients continues to decline and the regulatory frameworks for spray-applied RNAi biosticides develop in major agricultural markets. Bayer's access to SmartStax Pro's commercial performance data from millions of acres of US corn production creates the field-scale validation database that its RNAi technology development builds on and that competing RNAi developers must generate through their own trial programmes before their regulatory submissions can rely on the same depth of agronomic performance evidence.
The Regulatory Pathway and Commercial Timing
The regulatory frameworks governing spray-applied RNAi products differ substantially across the major agricultural markets whose adoption determines the commercial scale of the RNAi crop protection market. The US EPA's biopesticide registration pathway, which has approved the first spray-applied dsRNA products based on risk assessments that consider the sequence specificity of dsRNA and its environmental fate, creates the US regulatory precedent that other markets reference but do not automatically follow. The European Union's regulatory approach to dsRNA crop protection products, which must navigate both the pesticide regulation framework and the genetic modification regulatory considerations that some EU member states have applied to externally applied nucleic acid products, has been more cautious than the US biopesticide pathway and has created the regulatory uncertainty that has slowed EU market entry for spray-applied RNAi products.
Top 10 Companies in RNAi Crop Protection Globally
- Bayer CropScience: German agrichemical company with SmartStax Pro transgenic RNAi corn trait for Western corn rootworm control; its commercial deployment across US corn production and its ongoing RNAi trait development pipeline create the largest deployed commercial RNAi crop protection programme and the field-scale performance data that validates RNAi as a commercial crop protection mechanism.
- GreenLight Biosciences: US spray-applied RNA biopesticide company whose Colorado potato beetle dsRNA spray received EPA biopesticide registration; its cell-free RNA manufacturing technology and its regulatory pathway development create the commercial spray-applied RNAi platform whose cost and regulatory framework innovations determine the commercial viability of spray RNAi in commodity crop protection.
- Syngenta: Swiss agrichemical company with RNAi technology research and development programmes for crop protection; its seed treatment and crop protection portfolio and its genetic tool development create the major agrichemical company's RNAi crop protection investment whose commercial application would distribute through its established global crop protection distribution network.
- Corteva Agriscience: US agrichemical company with RNAi crop protection research in its technology pipeline; its seed genetics and crop protection integration and its commercial scale create the agricultural company position whose RNAi development builds on its established crop genetics and protection product commercialisation capabilities.
- BioCeres Crop Solutions: Argentine agricultural biotechnology company with RNAi-based crop protection research for South American crop systems; its developing market focus and its regulatory experience in South American agricultural biotechnology create the RNAi crop protection development position in the markets whose pest challenges and regulatory environments differ from the North American and European markets where most RNAi development has been concentrated.
- APS Environmental (RNA Biocontrols): Australian company developing spray-applied dsRNA products for pest control in Australian agriculture; its regulatory development under the Australian Pesticides and Veterinary Medicines Authority and its pest-specific dsRNA programmes create the Australian RNAi crop protection commercial development programme whose regulatory pathway progress informs commercial entry timelines in the Pacific region.
- RNAgri: Startup developing RNA-based crop protection products with improved environmental stability for outdoor application; its dsRNA formulation and stability technology that extends the field persistence of RNA-based active ingredients addresses the primary technical barrier that limits spray-applied RNAi efficacy under outdoor conditions whose UV radiation and enzyme activity degrade unprotected RNA.
- Apse: Australian RNA biocontrol company with dsRNA products for insect and virus management in horticulture; its horticultural application focus and its EPA and APVMA regulatory submissions create the specialty crop RNAi commercial development pathway whose higher value crop context supports the premium pricing that current RNA manufacturing costs require.
- Napigen: US plant synthetic biology company with plastid engineering for dsRNA production in crops; its plastid-based dsRNA expression system creates the in-plant dsRNA production approach that produces the pest control RNA directly in crop tissue at lower metabolic cost than nuclear transgene expression approaches, potentially improving the agronomic performance of transgenic RNAi traits.
- Evonik (Specialty Biosciences): German specialty chemical company with RNA formulation technology for agricultural applications; its lipid nanoparticle and encapsulation expertise from pharmaceutical RNA delivery applied to agricultural dsRNA stability creates the formulation technology that spray-applied RNAi needs to achieve the field stability whose current limitations constrain the commercial performance of unformulated dsRNA sprays.