Plants have an advanced immune system similar to animals such as humans, and when plants detect bacteria and viruses, they activate the immune system and control the infection of pathogens.Rain is an essential but risk factor for plant survival, as many of the pathogens that infect plants are transmitted by rain.However, it was unclear what kind of response plants would induce to rain.

　In this study, we first analyzed the genes expressed by the model plant Arabidopsis thaliana when exposed to rain, using a method called "RNA sequencing."As a result, plants expressed immune-related genes when exposed to rain.These genes were regulated by the CAMTA transcription factor.

　Since the function of CAMTA is regulated by Ca2 + (calcium ion), the research group thought that rain might increase the intracellular Ca2 + concentration in plants, and used Arabidopsis thaliana introduced with the GCaMP2 gene that can detect Ca3 + as fluorescence. Analysis.As a result, when rain is sensed by hair-like cells (trichomes) existing on the surface of leaves, a phenomenon called "calcium wave" in which an increase in Ca2 + concentration propagates in a wavy manner to the tissues around the trichomes. It was clarified that it induces, activates the immune system against trichome disease bacteria, etc., and controls the infection.

　This study shows that plants recognize rain as a risk factor, and that trichomes are responsible for it.These results not only contribute to understanding the formation of the immune system, but are also expected to be applied to disease control of agricultural products.

Paper information:[Nature Communications] Mechanosensory trichome cells evoke a mechanical stimuli–induced immune response in Arabidopsis thaliana