Systemic proteome remodeling in soybean during early nodulation: distinct responses in roots and leaves

Here, we aimed to deepen our understanding of the integration between root and shoot signaling during early nodulation by jointly analyzing proteome-level dynamics in roots and leaves of the wild type (WT) and the hypernodulating autoregulation-of-nodulation (AON) mutant, nark. To this end, we performed a time-course shotgun proteomics experiment in soybean roots and leaves of the same plants inoculated with Bradyrhizobium diazoefficiens. In WT roots, we observed proteome changes linked to calcium-dependent signaling, cellular reorganization, and nutrient allocation. In the leaves, isoflavonoid biosynthesis and immunity-associated responses were differentially regulated in the WT and nark mutant during nodulation. We hypothesize that AON signaling involves a complex interplay between isoflavonoids and immunity, which might be associated with jasmonic acid and/or systemic auxin transport.