911½ñÈÕºÚÁÏ

A newly discovered immune mechanism shows how plants use internal calcium signals to fight disease, potentially opening new pathways for stronger, more resilient crops.

Plants have a hidden defence system inside their cells

Feeding a growing global population sustainably will depend on resilient crops and reliable sources of plant-based protein. Advances in engineering biology are enabling scientists to better understand how plants defend themselves and translate these insights into more productive and sustainable agricultural systems.

Scientists at the Bezos Centre for Sustainable Protein and the Department of Life Sciences at 911½ñÈÕºÚÁÏ, working in collaboration with The Sainsbury Laboratory and Academia Sinica, have uncovered a previously hidden layer of plant immunity that could help support this transition.

By improving how plants defend themselves against disease, this research, , could enable higher yields, reduce reliance on pesticides, and strengthen the crops that underpin sustainable protein and future food systems.

The study shows that plants use internal signalling systems to defend themselves against disease, revealing a new layer of immunity that could reshape crop protection strategies.

“We discovered that plant immune receptors don’t just work at the cell surface — they can also target membranes surrounding organelles inside the cell, such as the chloroplast, and release calcium stored within them to activate defence,” explains Bozkurt. “This reveals a whole new layer of immune signalling that was previously unknown.”

The finding challenges long-held assumptions about how plant immune systems operate and opens new possibilities for developing crops that are more resilient, productive, and better suited to sustainable agriculture.

An artistic illustration of plant immune receptors (pink) targeting the chloroplast membrane and releasing the calcium stored inside. (credit ).

Scientists are rethinking how plants fight disease

For years, scientists believed that plant immune responses were triggered primarily at the outer boundary of the cell, where receptors form pores that allow calcium to flow in from outside.

“The prevailing view was that when plant immune receptors detect a pathogen, they assemble into pore-forming complexes at the plasma membrane and allow calcium to rush in from outside,” says Bozkurt. “Our study shows that this is only part of the picture.”

Instead, plants can also draw on internal calcium reserves. The research shows that an ancient family of immune receptors, known as NRG1, can target internal membranes and release calcium stored within organelles, enabling a more flexible and layered immune response.

A new layer of plant immunity. Left: most immune receptors are sent to the cell's outer boundary (PM) to let calcium flow in from outside (default system). Activated NRG1 receptors take a different route, targeting the chloroplast and releasing its internal calcium reserves. Right: live imaging shows activated NRG1 (magenta) docking onto a chloroplast (yellow) and draining its calcium store within an hour. (credit: Tarhan Ibrahim). 

Plants can trigger defence signals from within

At the centre of the discovery is NRG1, a helper immune receptor that forms channel-like structures inside the cell. These structures insert into membranes and act as channels that release calcium, triggering defence responses.

“What we show is that NRG1 resistosomes don’t only insert into the plasma membrane — they can also target chloroplast membranes and release the calcium stored inside these organelles.”

Calcium acts as a rapid signal in plant cells, activating defence pathways and, in some cases, triggering the controlled death of infected cells to stop disease spread. By accessing calcium from multiple internal stores, plants have a more sophisticated immune system than previously understood.

A new way to build stronger and more resilient crops

The discovery has important implications for agriculture, where many disease-resistance traits rely on this class of immune receptors. Until now, most efforts have focused on increasing receptor activity, rather than understanding where in the cell these responses occur.

“Our findings suggest a new design strategy: directing immune receptors to specific membranes — or multiple membranes — to build layered defences that are harder for pathogens to overcome.”

This approach could enable the development of crops with stronger and more durable resistance, improving yield stability and reducing losses caused by disease.

Stronger crops can support sustainable protein and future food

Research at the Bezos Centre for Sustainable Protein and the Microbial Food Hub focuses on how scientific advances can support the transition to sustainable protein and more resilient global food systems.

More resilient crops are critical to this transition. Protein-rich crops such as legumes, pulses, and cereals underpin many sustainable protein pathways, yet they are often vulnerable to disease. Improving their resistance can lead to higher yields, more reliable production, and better use of land.

Plant diseases reduce global crop yields by 20 to 40 percent, placing pressure on food supply, affordability, and land use. Strengthening natural plant immunity offers a pathway to reduce these losses while lowering reliance on chemical inputs.

Advances in engineering biology are enabling researchers to both uncover these fundamental mechanisms and translate them into practical strategies for crop improvement, from enhancing resistance traits to designing more robust agricultural systems.

“If we can engineer multi-layered immune responses that operate at different cellular locations, that makes evasion much harder,” Bozkurt notes. “More durable genetic resistance means less need for chemical intervention.”

Improving crop resilience is therefore directly linked to building food systems that are more affordable, resource-efficient, and scalable.

From discovery to real-world impact

While the research is still at a fundamental stage, it opens up new directions for crop science and engineering biology. The mechanism appears to be conserved across hundreds of millions of years of plant evolution, suggesting it could be applied across a wide range of crop species.

In the longer term, this insight could help enable crops that deliver higher yields with less land, require fewer chemical inputs, and support the scalable production of sustainable protein.

As global demand for food continues to grow, discoveries like this provide an important foundation for designing the next generation of resilient, productive, and sustainable agricultural systems.