PlasSeed: Gas Plasma for Seed Disinfection

In order to keep pace with the world's expanding population, global crop yields are required to double by 2050 and this requirement is made even more challenging by the rising global temperatures and emerging erratic weather patterns caused by climate change. To meet this challenge with minimal environmental impact, it is imperative that the productivity of agricultural land is increased through strategic and technological advances.

Seed-borne pathogens attack developing seedlings, compromising germination and plant establishment and ultimately reducing crop yield. As a result, seeds need to be disinfected and this is typically achieved by washing seeds with or without chemical additives, coating the seeds with fungicide, or soaking germinating seedlings in fungicide drenches. Such approaches have limited applicability as they can affect the germination of the seed and they are not effective in treating all diseases. In addition, due to stricter regulatory controls on the use of chemical agents, seed companies are in need of alternative means of disinfecting seeds without negatively affecting their viability.

PlasSeed proposes the use of gas plasma technology as a novel and potentially revolutionary means of disinfecting seeds. Gas plasma has been shown to have a broad range of antimicrobial properties and the technology offers a chemical-free, dry, low-energy alternative to existing seed disinfection techniques.

Low temperature plasmas are ionised gases containing cocktails of electrons, ions, radicals, excited species and photons under conditions that are far from thermodynamic equilibrium. As a result, plasmas can generate reactive environments at low temperature to initiate and catalyse chemical processes. Semiconductor fabrication, large area displays and energy-efficient lighting are examples of technologies that have been enabled by advances in plasma physics and engineering.

In recent years, advancements in the generation of nonthermal plasmas at atmospheric pressure has revolutionised plasma technology, opening up a host of new applications in biology and medicine. In particular, the capacity for microbial decontamination of a wide range of biotic materials (e.g. disinfection of wounds) has been amply demonstrated (Lu, X et al. 2016 Phys. Rep. 630, 1).

PlasSeed extends the use of this technology to the disinfection of seeds. This is a timely development that will address the pressing need for a scalable, effective, dry and chemical-free technology for seed disinfection. In collaboration with national and international industry partners, PlasSeed will develop plasma seed reactors and assess their efficacy in disinfecting a range of naturally contaminated seeds.

PlasSeed will perform experiments on batches of seed of large enough quantity (>30000 seeds) to warrant proper statistical results and naturally contaminated seeds will be used to overcome the shortcomings of artificial inoculation. The project will assess the efficacy of the treatment against epiphytic (superficial) and endophytic (deep-seated) pathogens, studying physical and biochemical changes triggered in the seeds and any long term effect on the growing plantlets.

The anticipated beneficiaries of this work include:

- Society: PlasSeed addresses an urgent problem faced by seed companies and contributes towards addressing the increasing pressure on global agriculture, food security and the environment. These are areas of global concern in which the government and UK funding bodies are strategically investing in. Successful completion of PlasSeed will contribute towards a sustainable future by providing an environmentally-friendly disinfection process for crop seeds that will have benefits on the health and quality of life of future generations.

- PlasSeed academic partners: Given the incipient state of the field of plasma agriculture, the proposed project pushes the current frontiers of gas plasma technology for the disinfection of seeds. Any breakthrough will create opportunities to lead in this rapidly growing field and will be welcome by the community. The academic partners will also establish a long-lasting collaboration in which complementary expertise held by each group will be combined to address more efficiently larger scientific and technological challenges in the future.

- PlasSeed industrial partners: With increasingly stringent regulations around the use of fungicides and concerns over xenobiotic residues in food production, seed companies are in urgent need of an innovative chemical-free disinfection process that can achieve its objectives without damaging the germination potential of seeds. PlasSeed promises one such solution and moreover, early access to and adoption of the technology by Elsoms Seeds and Bejo Zaden would give them an advantage over their competitors, positioning a UK company at the global forefront of seed disinfection.

- PlasSeed partners: All parties are committed to secure and exploit any intellectual property (IP) arising throughout the duration of the project. This could potentially provide another revenue stream for both the industrial partners and the academic institutions.