The stakes could hardly be higher. Global agriculture must deliver substantial yield gains by 2050 to feed a growing population while sharply reducing its environmental footprint. Today, pests and pathogens destroy between 20 and 40 percent of annual crop production, losses that are overwhelmingly managed with chemical pesticides carrying well-documented ecological and human health costs, from pollinator decline to contaminated waterways and rising greenhouse gas emissions associated with pesticide manufacture and application. RNA interference offers a fundamentally different approach: a mechanism that can be tuned with near-surgical precision to attack a single pest species while leaving beneficial insects, plants, and mammals untouched.

The underlying biology is elegant. RNAi is a natural gene-silencing pathway found across eukaryotes, first characterized by Andrew Fire and Craig Mello in the nematode Caenorhabditis elegans, work that earned the 2006 Nobel Prize in Physiology or Medicine. When a cell encounters double-stranded RNA, or dsRNA, an enzyme called Dicer slices it into small interfering RNAs. These fragments are loaded into the Argonaute-containing RNA-induced silencing complex, which uses one strand as a guide to find and degrade complementary messenger RNAs. If the dsRNA is designed to match a gene that is essential to a pest’s survival, ingesting it can shut down that gene and kill or debilitate the organism. Because the guide sequence can be chosen to match a target found only in the pest, the specificity of the approach far exceeds that of broad-spectrum chemical insecticides.

Two delivery strategies dominate the field. Host-induced gene silencing, or HIGS, builds the silencing construct directly into the crop’s genome, so the plant itself continuously produces dsRNA aimed at its attackers. Spray-induced gene silencing, or SIGS, instead applies dsRNA externally as a foliar spray, much like a conventional pesticide but with a biological active ingredient. HIGS delivered the first commercial success: the trait MON 87411, targeting western corn rootworm, was introduced in 2022 as part of SmartStax PRO maize, followed by additional RNAi-enabled products such as Bayer’s VT4PRO. SIGS reached the market more recently, when Calantha, developed by GreenLight Biosciences, became in 2023 the first foliar-applied RNA-based biopesticide registered by the United States Environmental Protection Agency, targeting the Colorado potato beetle.

Under controlled laboratory conditions, RNAi can achieve efficacy above 90 percent against susceptible target pests, a figure that rivals or exceeds many conventional insecticides. Yet responsiveness varies dramatically across taxa. Coleopteran insects such as beetles tend to be highly sensitive, while lepidopterans, the moths and butterflies that include some of the world’s most destructive caterpillar pests, often show weak or inconsistent responses. Research has traced this variability to several factors: differences in dsRNA uptake mechanisms, the activity of dsRNA-degrading nucleases in the gut and hemolymph, the efficiency of the core silencing machinery itself, and even the pH and enzymatic environment of the digestive tract. Some insects have also evolved outright resistance, as demonstrated in laboratory-selected populations of western corn rootworm and Colorado potato beetle, a reminder that any pest control technology must be deployed within a resistance management framework.

The second major barrier is environmental persistence. Naked dsRNA is fragile. It degrades rapidly in soil, on leaf surfaces, and in water, attacked by ubiquitous ribonucleases, ultraviolet radiation, and microbial activity. Studies of environmental fate have shown that dsRNA applied to soils typically dissipates within days, which is reassuring from an ecological risk perspective but problematic for growers who need a product to remain active long enough to protect the crop. This instability drives up the dose and frequency of application, and with it the cost, since dsRNA remains considerably more expensive to manufacture than conventional agrochemicals.

Formulation science is racing to close that gap. Nanoparticle carriers, including layered double hydroxide clay nanosheets, chitosan particles, lipid nanoparticles, carbon quantum dots, and engineered nanovesicles, can shield dsRNA from degradation and, in some systems, release it gradually over days or weeks. The BioClay platform, for example, has demonstrated prolonged protection against plant viruses and fungal pathogens by anchoring dsRNA on clay nanosheets that slowly desorb the payload. pH-responsive nanoparticles that release dsRNA in the alkaline midgut of target insects, cell-penetrating peptides that ferry RNA across membranes, and chemically modified dsRNAs that resist nuclease attack are all under active development. Meanwhile, microbial delivery systems are emerging as a complementary route: engineered bacteria and fungi can produce dsRNA in situ, and symbiotic microbes have been used to deliver silencing constructs to mosquito larvae and other targets.

Cost, too, is falling. Traditional dsRNA production relied on in vitro transcription, which is expensive at agricultural scale. Bacterial fermentation using strains optimized for dsRNA accumulation, cell-free production systems, and engineered microbes such as Corynebacterium glutamicum equipped with phage expression machinery have all been shown to yield long dsRNAs suitable for pest control at a fraction of the cost. Computational tools for dsRNA design, including multi-target chimeric designers and off-target prediction software, are simultaneously improving the precision and safety of candidate molecules by screening against the genomes of non-target organisms such as pollinators and natural enemies.

The third barrier is regulatory, and it may be the most consequential. Because RNAi products straddle the boundary between biotechnology and crop protection, jurisdictions classify them inconsistently: as biochemical pesticides, as plant-incorporated protectants, or as novel active substances requiring full GMO-style assessment. The United States has moved fastest, registering both transgenic RNAi traits and sprayable dsRNA products, while the European Union and many other regions are still defining their frameworks. This patchwork creates uncertainty for developers, delays market entry, and risks leaving growers in some regions without access to tools approved elsewhere. Review authors and other commentators have called for global regulatory cohesion, arguing that harmonized, science-based risk assessment frameworks are essential if RNAi biopesticides are to contribute meaningfully to sustainable food production and to the United Nations Sustainable Development Goals.

None of these challenges diminishes the underlying promise. RNAi aligns with the central demands of twenty-first-century agriculture: high specificity, low residues, minimal impact on non-target organisms, and compatibility with integrated pest management. The technology extends beyond pest killing, with demonstrated applications in improving shelf life, enhancing abiotic stress tolerance, modifying oil composition, and managing fungal, viral, and nematode pathogens. What the new review makes clear is that the remaining obstacles are engineering and governance problems rather than fundamental biological ones. If nanoparticle formulations, cheap microbial production, and coherent regulation mature together, RNA interference could indeed become a cornerstone of next-generation agriculture, turning a Nobel-winning discovery into the everyday toolkit of the sustainable farm.

Subject of Research: RNA interference as a sustainable crop protection technology and the barriers to its field deployment

Article Title: RNAi: the next wave of green agriculture, challenges, and bridging the translational gap

Article References: Abdullah, Z. K., Kong, L. L., Ariffin, N., & Wong, M. Y. (2026). RNAi: the next wave of green agriculture, challenges, and bridging the translational gap. Plant Cell Reports, 45(9), Article 271. https://doi.org/10.1007/s00299-026-03939-x

Image Credits: AI Generated

DOI: 10.1007/s00299-026-03939-x

Keywords: RNA interference, RNAi biopesticides, double-stranded RNA, spray-induced gene silencing, host-induced gene silencing, crop protection, sustainable agriculture, nanoparticle delivery, dsRNA stability, pest control, regulation, Plant Cell Reports

The core of the story lies in RNA interference, or RNAi, a gene-regulation system shared across much of life. Small interfering RNAs and microRNAs can be loaded into Argonaute proteins to form silencing complexes that seek out and destroy matching messenger RNAs. What has stunned researchers is that these molecules do not respect species barriers. A fungal pathogen can ship its own small RNAs into a plant cell, where they hijack the host’s Argonaute machinery and switch off immunity genes. Conversely, a plant can package its small RNAs into extracellular vesicles and send them into an invading fungus, where they silence the very genes the pathogen needs to cause disease.

The evidence is strikingly specific. The gray mold fungus Botrytis cinerea secretes small RNAs such as Bc-siR3.1 and Bc-siR5 into plant cells, where they co-opt the host AGO1 complex to suppress immunity-related genes. The wheat rust pathogen Puccinia striiformis delivers a microRNA-like RNA called Pst-milR1 that silences PR2, a gene encoding beta-1,3-glucanase involved in degrading fungal cell walls. In the banana-wilting Fusarium oxysporum system, fungal milRNAs target banana transcription factors and receptor-like kinases, dismantling early defense signaling. Rhizoctonia solani deploys a battery of milRNAs against rice, suppressing vacuolar sorting receptors, NB-ARC immune receptors, and F-box proteins to blunt the hypersensitive response. Even Valsa mali, the apple canker pathogen, uses a single milRNA to silence two receptor-like kinases and reduce reactive oxygen accumulation and callose deposition in host tissue.

Crucially, the traffic runs both ways. Plants selectively load small RNAs into extracellular vesicles with the help of RNA-binding proteins including AGO1, the helicases RH11 and RH37, and the annexins ANN1 and ANN2, which sort, stabilize, and transport the cargo. Encapsulation shields the RNA from extracellular nucleases during the journey. In the Brachypodium distachyon and Fusarium graminearum system, researchers identified 258 plant-derived small RNAs that target fungal messenger RNAs and significantly reduce pathogenicity. Wheat roots even send microRNAs into the beneficial fungus Clonostachys rosea, where they fine-tune fungal secondary metabolism rather than triggering defense, showing that RNA exchange also shapes cooperative relationships, not just conflict.

Bacteria play this game too, though the evidence is younger. The rice pathogen Xanthomonas oryzae pv. oryzicola packages a small RNA called Xosr001 into outer membrane vesicles, which deliver it into rice cells to silence OsJMT1, a jasmonate metabolism gene, thereby suppressing stomatal immunity. In the opposite direction, Arabidopsis plants have been shown to silence virulence genes of Pseudomonas syringae, reducing bacterial colonization and impairing stomatal reopening, with the silencing RNAs exported through both vesicle-associated and non-vesicular routes. Plant-derived small RNAs can also suppress gene expression in Ralstonia pseudosolanacearum, the agent of bacterial wilt. Even mutualistic partnerships show RNA crosstalk: Bradyrhizobium japonicum produces tRNA-derived fragments that accumulate in soybean nodules and use the host AGO1 machinery to regulate plant transcripts involved in nodulation.

Viruses occupy a special place in this landscape. Because viral RNA replicates continuously inside host cells, the review’s authors treat plant-virus systems as a closely related but mechanistically distinct model rather than classical cross-kingdom transfer. Still, the dynamics are instructive. Plants process viral double-stranded RNA with Dicer-like enzymes into virus-derived small interfering RNAs that guide sequence-specific degradation of viral genomes. Viruses fight back with silencing suppressor proteins such as the NS3 protein of Rice stripe virus, which binds small RNAs and interferes with microRNA biogenesis. Virus-derived siRNAs from Rice black-streaked dwarf virus directly target host genes in rice and maize, while virally activated siRNAs extend RNA regulation to endogenous plant transcripts during infection, creating layered, bidirectional control networks.

These discoveries have crystallized into three agricultural technologies that share a common RNAi mechanism but differ in delivery. Spray-induced gene silencing, or SIGS, applies double-stranded RNAs directly onto plant surfaces, where they are taken up by tissues and silence invading pathogens. It is non-transgenic, rapid, and flexible, and has been shown to suppress gray mold, Fusarium head blight, stem rot, powdery mildew, and late blight across cereals, vegetables, fruits, and ornamentals. Artificial vesicles and nanocarriers such as layered double-hydroxide nanosheets dramatically extend the persistence of sprayed RNAs, with encapsulated double-stranded RNAs protecting tomato and grape tissues for up to ten days and grape leaves for up to twenty-one days.

Host-induced gene silencing, or HIGS, takes the opposite approach: the plant itself is genetically engineered to continuously produce silencing RNAs directed at pathogen genes. Stable HIGS lines have delivered durable resistance in sugarcane against Pokkah boeng and smut, in rice against Bakanae disease and blast, in potato against late blight, and in apple against ring rot. In one notable strategy, transgenic Arabidopsis expressing short tandem target mimics effectively blocked the immune-suppressing small RNAs of Botrytis cinerea, reducing gray mold infection. HIGS offers long-lasting, tissue-specific protection, but it inherits the regulatory hurdles, biosafety debates, and public concerns that surround genetically modified crops, and it demands years of development time.

The newest and perhaps most intriguing strategy is microbe-induced gene silencing, or MIGS, which recruits beneficial microorganisms as living RNA delivery vehicles. Engineered Trichoderma harzianum strains colonizing the rhizosphere produce small RNAs that silence virulence genes in Verticillium dahliae and Fusarium oxysporum. Even more remarkably, engineered Bacillus subtilis and Pseudomonas putida can package double-stranded RNAs into extracellular vesicles and deliver them across kingdoms to fungal pathogens, suppressing Botrytis and Verticillium infections in Arabidopsis and tomato. Because microbes protect their RNA cargo from environmental degradation and can be produced at relatively low cost, MIGS could overcome the two biggest weaknesses of sprayed RNA: instability and expense.

The field is moving from laboratory proof-of-concept toward commercial reality. RNA-based pesticides are a rapidly growing industry, and China has officially released the first batch of registered RNA pesticide products, targeting Tobacco Mosaic Virus. The review argues that the safest and most effective targets will come from cross-kingdom small RNAs themselves, molecules already filtered through millions of years of co-evolution, whose natural trafficking suggests low off-target risk and environmental compatibility. Pairing these evolutionarily optimized sequences with microbial bio-factories for production and delivery, the authors contend, could dissolve the techno-economic barriers that have slowed RNA biopesticides. Significant questions remain, including how RNAs are packaged and recognized by recipient cells, how stable they are under field conditions, and what ecological effects engineered microbes might have on soil biodiversity. But the direction is clear: the quiet molecular conversation between plants and microbes is becoming a blueprint for agriculture that protects crops with the precision of a key in a lock rather than the blunt force of a chemical spray.

Subject of Research: Cross-kingdom RNA communication between plants and microbes and its application in RNA interference-based crop protection

Article Title: Cross-kingdom RNA in plant–microbe interactions: from molecular interactions to next-generation crop protection

Article References: Cross-kingdom RNA in plant–microbe interactions: from molecular interactions to next-generation crop protection. (n.d.). https://doi.org/10.1007/s44154-026-00337-x

Image Credits: AI Generated

DOI: 10.1007/s44154-026-00337-x

Keywords: cross-kingdom RNA, RNA interference, plant-microbe interactions, spray-induced gene silencing, host-induced gene silencing, microbe-induced gene silencing, small RNAs, extracellular vesicles, RNA pesticides, fungal pathogens, plant immunity, sustainable agriculture