When soil inorganic phosphate (Pi) availability is low, plants upregulate Pi starvation response (PSR) genes to maintain Pi-homeostasis. Recent evidence shows that inositol pyrophosphates (PP-InsPs), energy-rich molecules have seven and eight groups (InsP7 InsP8), aid in PSR gene regulation. InsP8 levels are controlled by conserved enzymes add or remove group from its precursors. In yeast, Siw1...