Plant RNA Virus-Based Expression Vectors for Sustainable Biomanufacturing: Viral Chassis, Process Performance, and Engineering Perspectives

Plant RNA virus-based expression vectors are emerging as modular biological chassis for rapid, scalable, and sustainable production of recombinant proteins in plants. From a chemical and biological engineering perspective, these systems integrate upstream vector design, host selection, inoculation strategy, intracellular amplification, product accumulation, and downstream recovery into a flexible biomanufacturing workflow. Compared with stable transformation, RNA viral platforms shorten development timelines, enable high-copy amplification, and support deployment in whole plants, plant tissues, cell cultures, and specialized secretion systems. The studies reviewed here show that Potyviridae, Virgaviridae, Alphaflexiviridae, Tombusviridae, Bromoviridae, Secoviridae/Comoviridae, and emerging Kitaviridae-derived systems have been engineered to produce reporters, vaccine antigens, virus-like particles, antibodies, nanobodies, enzymes, therapeutic proteins, metabolic enzymes, genome-editing components, and agronomic regulators. Reported outputs span qualitative accumulation to process-relevant yields, including approximately 5 g/kg fresh biomass, 3-5 mg/g fresh weight, 30 -80% of total soluble protein, and hundreds of mg/kg fresh tissue, depending on vector architecture, host chassis, insert properties, and delivery mode. We discuss these platforms as bioengineering systems rather than only virological tools, emphasizing manufacturing speed, process scalability, product classes, yield determinants, purification and quality-control challenges, biosafety, and opportunities for synthetic biology, computer-aided vector optimization, and sustainable plant-based production.