activates peroxidase-mediated cell wall modification to inhibit root cell elongation.

The molecular mechanism of beneficial bacterium -mediated root developmental remain elusive. elicited extensively transcriptional changes but inhibited primary root elongation in . By analyzing root cell type-specific developmental markers, we demonstrated that affected neither overall organization nor cell division of primary root meristem. The cessation of primary root resulted from reduction of cell elongation, which is probably because of bacterially activated peroxidase that will lead to cell wall cross-linking at consuming of HO. The activated peroxidase combined with downregulated cell wall loosening enzymes consequently led to cell wall thickness, whereas inhibiting peroxidase restored root growth under inoculation. We further showed that peroxidase activity was probably promoted by cadaverine secreted by . These results suggest that inhibits root elongation by activating peroxidase and inducing cell wall modification in , in which cadaverine released by is a potential signal compound.