Mycorrhizal Signals Promote Root Development Dependent on LysM-Receptor Like Kinases in Rice

Roots play a fundamental role in plant growth and development, serving various functions, including anchoring, water absorption, nutrient uptake, and adaptation diverse environmental conditions, such as abiotic stresses and biotic interactions. Arbuscular mycorrhizal (AM) fungi release diffusible signaling molecules known as mycorrhizal factors (Myc factors) to establish communication with plants. Extensive research has established that Myc factors play a pivotal role in orchestrating root architectural changes before fungal colonization occurs. In this study, we investigate the impact of the Myc factor CO4 on the architectural modifications of rice roots. Our findings reveal that CO4 actively promotes the development of crown roots and lateral roots in wild-type rice plants. Furthermore, we have identified that pivotal role of receptors such as OsCERK1, OsMYR1, and OsCEBiP in mediating the stimulatory effects of CO4. Knockout mutants of these receptors exhibit a significant reduction in the number of lateral roots and crown roots with lateral roots, along with decreased sensitivity to CO4. Conversely, the overexpression of OsMYR1 leads to a substantial increase in lateral roots and crown roots with lateral roots, even in the absence of CO4 treatment. We propose that CO4-induced root architecture development offers promising opportunities for enhancing lateral root growth, which, in turn, can promote nutrient uptake through direct Myc factor application.