Ca2+-dependent processing of immunomodulatory peptides ($) (Science)

Plants are sessile organisms that have evolved an extraordinary immune system to optimally adapt to the risky environment, which includes hazards such as insect chewing, weather damaging, and pathogen invasion. But the signaling mechanism of how the physical damage of cells triggers the intracellular defense response remains to be elucidated. Recently Hander el al. demonstrated that physical damage of plant cells led to the loss of cell-membrane integrity, inducing the influx of extracellular Ca²⁺ into the cytosol. Intracellular Ca²⁺ instantly and spatiotemporally activated the cytosol-localized matacaspases such as MC4, which in turn cleaved and released wound-immunomodulatory peptides including PEP1 from its precursors. PEP1 binds its classic receptor PEPRs to induce innate immunity-like response. This discovery reveals a more detailed mechanism of PEPRs related defense-response, and also shows us the potential targets to improve disease resistance of high-performance crop varieties. (Summary by Nanxun Qin). Science 10.1126/science.aar7486