Daidzin from Pueraria thomsonii regulate root plasticity and cell proliferation

Root plasticity is essential for optimizing crop yields and ensuring survival under stress. However, the regulatory roles of root-enriched secondary metabolites in developmental processes have remained largely unexplored. Pueraria thomsonii , a leguminous species distinguished by its rare tuberous roots, exhibits remarkable isoflavonoid accumulation. Chemical quantification and in vitro functional analyses have identified daidzin as a key regulator of root architectural plasticity in this species. Using an integrated approach combining Arabidopsis thaliana (L.) root phenotyping system, cellular thermal shift assays (CETSA) and thermal proteome profiling (TPP), daidzin was demonstrated to modulate root development via stem cell-related processes and auxin signaling pathways. Specifically, daidzin led to the reduced auxin levels, silenced DR5::GFP expression in the stele, and suppressed PIN protein expression accompanied by a lateral shift in PIN2 polarity. Furthermore, daidzin decreased SHR, SCR, PLT1, and PLT2 protein levels while increasing WOX5 and CYCD6;1 accumulation. In the wox5 mutant, daidzin inhibited root elongation, whereas in the p35S:WOX5-GR transgenic line, it enhanced root elongation and attenuated starch granule degradation. These findings reveal that WOX5 functionally counteracts daidzin-mediated root growth inhibition. Furthermore, daidzin stimulated cell proliferation in Pueraria thomsonii (Benth.) and induced root thickening in Panax quinquefolius (L.). Collectively, these results suggest that daidzin's coordinates root architectural plasticity by modulating auxin transport, polarity, and stem cell niche maintenance, highlighting its potential as a valuable tool for enhancing root development in economically important crops.