Abstract
3',5'-cyclic guanosine monophosphate (cGMP) and hydrogen peroxide (H₂O₂) function as the important signaling molecule which promote the lateral root development of Arabidopsis thaliana. In this study, interestingly, application of 8-Br-cGMP (the membrane permeable cGMP analog) promoted the endogenous H₂O₂ production. In addition, the decrease of endogenous H₂O₂ also inhibited the effect of cGMP on the lateral root development. Thus, H₂O₂ maybe act as a downstream signaling of cGMP molecule which is involved in the lateral root development of Arabidopsis. We further found that H₂O₂ affected cGMP modulating polar auxin transport. When the endogenous H₂O₂ level was inhibited, the effect of cGMP on the acropetal auxin transport and the basipetal auxin transport was removed. Moreover, pin2 was insensitive for cGMP and H₂O₂ suggesting that PIN2 protein plays an important role in cGMP and H₂O₂ modulating the lateral root development of Arabidopsis.