Lighting the path: how light signaling regulates stomatal movement and plant immunity

Abstract

Stomata, the small pores on the surfaces of leaves and stems, are crucial for gas exchange in plants and also play a role in defense against pathogens. The stomatal movement is not only influenced by surrounding light conditions but also by the presence of foliar pathogens. To put it more crisply, certain light wavelengths such as blue or strong red light, cause stomatal opening, which tragically makes it easier for bacteria to enter through opened stomata and causes disease progression in plants. Illumination of blue or intense red light autophosphorylates phototropin, a blue light photoreceptor protein kinases that in turn activates signaling cascade to open stomata. Undoubtedly stomatal defense is a fascinating aspect of plant immunology, especially in plant-foliar pathogen interaction. During these interactions, stomata fundamentally serve as entry points for intrusive pathogens and initiate plant defense signaling cascade. The present review highlights how the light-activated photoreceptors like cryptochromes (CRYs), phytochromes (phys), and UV-receptors (UVRs) influence the stomatal movement and defense signaling after foliar pathogen intrusion. It also explores the link between stomatal defense, light signaling, and plant immunity, which is vital for safeguarding crops against pathogens.