bioRxiv · 2026-05-23
Scientists discovered that a single plant protein called CCaMK acts as a master switch controlling whether beneficial soil fungi can colonize rice roots, even overriding the plant's normal anatomical barriers. This helps explain how plants regulate their underground fungal partnerships and could eventually lead to crops that form stronger, more efficient symbioses without added fertilizer.
An always-on version of the CCaMK protein restored full fungal colonization in rice mutants that normally block the symbiosis, confirming CCaMK acts downstream of the D14L signaling pathway.
Activating CCaMK allowed fungi to invade normally restricted root zones (the meristematic zone and endodermis), showing CCaMK determines which root tissues are open to fungal entry.
Even with colonization restored, arbuscules (the nutrient-exchange structures) were less developed and showed abnormal fungal septation, revealing a CCaMK-independent role for D14L in arbuscule maturation.
