Strigolactone inhibits hydrogen peroxide and plasma membrane H+-ATPase activities to downregulate adventitious root formation in mung bean hypocotyls

Abstract

Strigolactones regulate root development and are known to inhibit adventitious root formation. However, the hormonal targets of strigolactones during adventitious rooting are yet to be determined. As a signal molecule, H2O2 stimulates adventitious rooting. On the other hand, plasma membrane H+-ATPase is involved in several hormonal signals that are linked to root development. This study evaluated the influence of a synthetic strigolactone (rac-GR24), H2O2, and plasma membrane H+-ATPase on adventitious root formation in mung bean hypocotyls. We also determined if H2O2 and plasma membrane H+-ATPases are possible hormonal targets in strigolactone-mediated inhibition of adventitious rooting. The results confirm the inhibitory role of strigolactones and the enhancing influence of H2O2 on adventitious rooting while also suggesting that plasma membrane H+-ATPase activity is necessary and may be employed to regulate adventitious rooting. Also, rac-GR24 diminished endogenous H2O2 content by inhibiting NOX and SOD activities while also inhibiting plasma membrane H+-ATPase activity. Therefore, we conclude that interference with H2O2 signaling and plasma membrane H+-ATPase activity may serve as a potent hormonal mechanism that may be employed by strigolactones to downregulate adventitious rooting in mung bean hypocotyls.