Similar to human vaccination, pre-exposure of plants to specific chemical signals can induce long-lasting immunological memory. This form of acquired immunity is based on a ‘priming’ of the plant’s innate immune system, enabling a faster and/or stronger immune response against attempted infection by pathogens. Unlike vaccination in humans, however, immune priming in plants typically offers broad-spectrum protection against a range of diseases. Moreover, the underpinning mechanisms are largely different to those driving acquired immunity in humans, involving a combination of immune signalling mechanisms and epigenetic mechanisms that appear to be conserved between taxonomically unrelated plant species. As such, immune priming provides a multi-mechanistic form of broad-spectrum disease resistance that has strong potential for exploitation in crop protection strategies. Unfortunately, priming by chemical agents is often associated with negative side-effects on plant growth and yield, which have hampered the commercial exploitation of these agents. The current ERC Proof-of-Concept (ERC-PoC; ‘ChemPrime’) builds on previous discoveries from a ERC consolidator project (‘Prime-A-Plant’), which has generated novel insights about the molecular and epigenetic mechanisms controlling chemically induced immune priming and associated trade-offs on plant growth. The current ChemPrime project aims to consolidate this knowledge by generating translatable knowledge about the mode of action of chemical priming agents, and designing a strategy for the integration of chemical priming agents in crop protection strategies.
ChemPrime is divided into two separate Work Packages (WPs). The first WP involves further molecular-genetic research to identify novel breeding targets to improve the efficiency by which the resistance-inducing β-amino acids β-aminobutyric acid (BABA) and R-β-homoserine (RBH) induce broad-spectrum disease resistance, while the second WP addresses the opportunities for developing a commercially viable crop protection strategy with the ultimate objective to find industry partners to advance the commercialisation of chemically induced immune priming in crops. WP1 of the project has uncovered new regulatory genes in the perception, signalling and trade-offs associated with BABA- and RBH-induced resistance, which can be used by crop breeding companies to select for crop varieties that respond optimally to (combinations of) these resistance-inducing chemicals. Evidence for the success of WP1 is illustrated by a recent publication in Molecular Plant (Schwarzenbacher et al. 2020). Using a range of knowledge exchange activities, WP2 has engaged with the Agri-tech community to seek advice about application opportunities for chemical priming agents, as well as other agricultural and horticultural stakeholders to identify potential adoption barriers. Stakeholders were engaged through a number of different activities, which provided very helpful information about the potential market opportunity for new protective strategies, and information relating to potential barriers or bottlenecks (such as regulation). These activities were: 2 Integrated Pest Management-related events jointly hosted with the Agri-food arm of the Knowledge Transfer Network and opinion surveys of attendees, as well as 5 long-form interviews with key stakeholders who have extensive knowledge and experience of the sector. These activities have given us a better understanding of the exploitation potential of chemical priming agents, as well as stakeholder demands and expectations of new crop protection strategies.
Two key outcomes of the project are the identification of targets for IP protection (for which the University’s Commercialisation team have been engaged, and the relevant internal processes initiated), and the establishment of a new collaboration with the international vegetable seed company, Enza Zaden, to develop a commercial route for the delivery chemical and epigenetic strategies to exploit immune priming in lettuce against downy mildew diseases. The preferable option for use of the product based on our current findings would be indoor controlled growing. We are currently seeking further funding from UK research councils to consolidate our collaboration with Enza Zaden, plus a number of other relevant companies in the supply chain (including APS Salads, who were one of the interview participants for this project). In addition, we are exploring funding opportunities to start a spin-off company that is specialised in the (bio)chemical production of bio-active β-amino acids.
