Vesicle Trafficking Orchestrates Root Nodule Symbiosis.

The establishment and maintenance of root nodule symbiosis (RNS) are orchestrated by sophisticated vesicle trafficking networks that coordinate rhizobia infection, nodule organogenesis, and symbiosome development. Central players include Rab and ROP GTPases, soluble N-ethylmaleimide-sensitive factor attachment protein receptors, synaptotagmins, and exocyst complexes, which mediate spatiotemporal membrane identity transitions and enable the formation of a unique nitrogen-fixing organelle termed symbiosome. Additionally, lineage-specific secreted cargoes, such as nodule-specific cysteine-rich peptides in inverted-repeat-lacking clade legumes, drive irreversible bacteroid differentiation and maintain bacteroid viability. Despite developmental architectures diverge across species, a core set of trafficking components is evolutionarily conserved. This review catalogues and contextualises all of endosomal regulators currently known to be required for RNS. We also discuss potential agricultural applications of vesicle trafficking-based strategies in the RNS.