Molecular targets for strengthening plant immunity
Plants are not only a primary source of food, they also help to regulate the climate and provide environments for a variety of species. Ensuring plant health is therefore critical to our overall well-being. This was the focus of the DeCaETI project, which explored the role of calcium in plant immunity. While calcium helps to trigger defence responses against detected pathogens, the precise means by which this response is regulated is still not widely understood. “We wanted to find out more about how calcium signalling is directly activated by plant nucleotide-binding leucine-rich-repeat receptors (NLRs),” explains Yuxiang Jiang(opens in new window), currently a professor at Beijing Forestry University(opens in new window) and a member of the EU-funded DeCaETI project. These plant NLRs are intracellular immune receptors that detect pathogen attacks in the first place. “Elucidating this specific link between pathogen perception by NLRs and the initiation of calcium signalling is essential for understanding the early steps of a robust immune response,” adds Jiang.
Calcium dynamics and intracellular immune receptors
The DeCaETI project, coordinated by Pingtao Ding’s Laboratory(opens in new window) at the Institute of Biology Leiden(opens in new window), Leiden University(opens in new window) and supported by the Marie Skłodowska-Curie Actions(opens in new window) programme, sought to shed new light on this link. “We wanted to decode the calcium dynamics activated by these intracellular immune receptors (NLRs) and characterise the role of NLRs in producing calcium signatures,” explains Jiang. “We also wanted to identify calmodulins (calcium-binding proteins) and other calcium-responsive proteins that decode these calcium signatures during immune activation mediated by NLRs.” To do this, Jiang applied several advanced techniques in this research. To image calcium dynamics in cells upon immunity stimuli for example, he and his colleagues constructed a marker that highlighted this dynamic in the nucleus and cytosol simultaneously. “We focused on a specific group of NLRs, namely the helper NLRs,” says Jiang. “We found that different helper NLRs can induce immunity gene expression at different time points, which reflects both spatial and temporal regulatory properties of plant innate immunity, and thus enabling the plant to adopt a step-by-step strategy to defend itself.”
Supporting plant health with helper NLRs
These findings could have important implications for how we support plant health, with helper NLRs representing an important target for strengthening immunity response. “By identifying a powerful, universal target, this research could directly advance intelligent crop breeding,” notes Jiang. “Helper NLRs act as central amplifiers of plant immune response. By providing evidence that they are a key leverage point, we enable strategies that could enhance broad-spectrum disease resistance.” For example, breeders could use next-generation gene editing (such as improved CRISPR, prime editing) or marker-assisted selection to optimise helper NLR genes, creating crops with stronger, more durable innate immunity. This would also reduce reliance on chemical pesticides and increase yield stability.
Applying findings to key crops
Next steps include translating the project’s discoveries from the lab to the field. “Primarily, we would like to apply our findings to key crops like tomatoes and barley by using gene-editing techniques to engineer optimised helper NLRs,” adds Jiang. A chemical screening programme to identify and develop small-molecule compounds that can safely and effectively stimulate helper NLR activity is also in the pipeline. “This dual approach – genetic breeding and agrochemical innovation – will provide practical tools to fortify crop resilience, reduce pesticide dependence and integrate these solutions into sustainable agricultural practices,” says Jiang.
