This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Energy production in our cells, oxygen traveling in our blood and immune cells fighting infection all depend on iron, an essential mineral that enters the food chain when plants absorb it from soil. But iron is often scarce—likely increasingly so as global weather and temperatures continue to change—and we aren't the only ones that need it.
Microbes that live on and around plants also need iron. Plants are then forced to strike a delicate balance between using iron to defend themselves against microbes and retaining it to maintain health. New Salk research reveals a dual-purpose protein called SRF3, which both restores iron balance after microbial invasion and ensures that the plant's immune response is just right.
The study, published in Science Advances on Oct. 14, 2026, provides insights into plant resilience that could shape future agricultural efforts to feed a growing global population with nutritious crops. "Because plants are the main entry point for iron into our food supply, understanding how they control iron is important not only for plant health but also for agriculture and human nutrition," says co-corresponding author Wolfgang Busch, Ph.D., a professor and holder of the Hess Chair in Plant Science at Salk. Busch, alongside co-corresponding author Matthieu Pierre Platre, Ph.D., has been studying how plants control iron for a while.
The two published a paper together in Nature Communications in 2022, in which they first identified SRF3 as mediating plant responses to microbes. SRF3 lives on the surface of plant cells. There, it is firmly anchored in the plasma membrane, the cell's outer boundary, where it can receive environmental cues and signals.
The 2022 Salk study revealed that SRF3 could sense iron levels and direct root growth accordingly and suggested that the SRF3 protein is also involved in nutritional immunity responses. "It became very interesting because microbes and plants are fighting for limited iron in the soil," explains Busch. "So, microbes start invading plants to steal iron from their cells, while plants are forced to defend themselves and protect their iron stores.
We were really interested in this tug of war." What was happening at the molecular level and the mechanisms behind SRF3's involvement remained unknown—until now. The researchers started with Arabidopsis thaliana, a small flowering plant that is easy to grow and serves as a popular laboratory stand-in for other plants, including important crops like wheat or corn. Through a series of experiments—from flagging and tracking iron levels in cells to visualizing the movement of SRF3 to removing SRF3 completely and observing the consequences—they laid out the mechanism by which SRF3 balances immune defense and iron maintenance.
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