Mitochondrial small heat shock protein mediates seed germination via thermal sensing

Significance The propagation of most flowering plant species is determined by the success of seed germination, which is of both economic and ecologic importance. Mitochondria are the energy resource and crucial organelles for plant seed germination. Studying the underlying mechanism is important for us to understand the basic principles of plant development and improve crop yields. Here we identify HSP24.7 as a central activator for temperature-dependent seed germination. HSP24.7 modulates cytochrome C/C 1 production in the mitochondrial electron transport chain and induces the generation of reactive oxygen species, which accelerates seed germination. Our work provides a comprehensive framework of how mitochondria regulate seed germination in response to the dynamics of environmental temperature.