Emerging roles of inositol pyrophosphates in plants: from environmental stress acclimation to hormonal responses and terrestrialization

Diphosphate-containing inositol phosphates, also known as inositol pyrophosphates (PP-InsPs), are energy-rich signaling molecules that orchestrate an ever-expanding repertoire of cellular processes in eukaryotes. Recent advances in analytical methodologies have been instrumental in detecting these messengers in plant extracts and characterizing the enzymology underlying PP-InsP metabolism in plants. Collectively, these developments have been critical to establishing PP-InsPs as emerging cellular messengers that control a broad spectrum of physiological processes, including immunity, nutrient homeostasis, growth, and development in plants. In this Tansley insight, we synthesize current knowledge on the molecular basis of PP-InsP metabolism and their physiological functions, and outline potential future research directions. We further discuss the putative role of PP-InsPs in plant terrestrialization, a pivotal evolutionary transition that fundamentally reshaped Earth's biosphere approximately half a billion years ago.