Ca²⁺ Signalling in Plant Biotic Interactions

Recently, with the emergence of new tools such as the development of genetically encoded Ca²⁺ sensors that can monitor Ca²⁺ fluxes in real-time and improvements in confocal microscopy that allows for much higher spatial resolution, the field of Ca²⁺ signalling has gained significant momentum. We believe it is timely to propose a Research Topic for Frontiers in Plant Science dedicated specifically to Ca²⁺ signalling in the context of plant biotic interactions. Plants utilize Ca²⁺ to respond to many external threats, but also when establishing beneficial interactions with microbes. Ca²⁺ signalling includes Ca²⁺ fluxes, i.e. Ca²⁺ channels/pumps and their regulation and interaction with other proteins, as well as downstream signalling triggered by the influx of Ca²⁺, such as Ca²⁺ binding proteins, kinase activation and Ca²⁺-regulated transcription factors/regulators. One focus will be the interaction of plants with pathogenic microorganisms. Recently, there have been some breakthroughs in Ca²⁺ signalling in the context of PTI. But there are many unanswered questions in ETI, systemic signalling, interactions with necrotrophic pathogens, and insects. Another area of interest would be interactions of the plant root, such as with soil microorganisms and nematodes. Besides pathogenic interactions, Ca²⁺ signalling in the context of symbiotic interactions should also be included. How can plants distinguish between friend and foe? Finally, another aspect could be the effects of environmental factors on the outcome of plant-pathogen interactions.

This Research Topic aims to collect articles addressing the latest advances in Ca²⁺ signalling research that focus on but are not limited to the following aspects:

·      Ca²⁺ fluxes, channels/pumps at the plasma membrane, tonoplast, nucleus, or organelles

·      Ca²⁺ signalling, receptor-channel complexes, immediate downstream signalling upon perception

·      Ca²⁺ signalling in response to biotroph and necrotrophy pathogens

·      The role of Ca²⁺ in long-distance/systemic signalling

·      Ca²⁺ signalling in the root upon pathogen/symbiont interactions

·      The role of Ca²⁺ signalling in connecting environmental effects to biotic interactions

·      Plant-insect interactions