An environmental-friendly resistance inducer in crop protection: V2C MXene nanosheets induce plant resistance to Ralstonia solanacearum via the ET/JA signaling pathway

Frequent or excessive use of synthetic pesticides can easily lead to pollution of soil and groundwater in management of soil-borne diseases. An environmental-friendly vanadium carbide MXene nanosheets (V 2 C-NSs) have been widely studied in the field of nanomedicine and biomaterials. However, few studies have shown has direct effects of V 2 C-NSs on crop protection and induces plant resistance to disease. In this study, V 2 C-NSs were first prepared by artificial synthesis and characterized, and the resulting material displayed an excellent Tyndall effect. The ability of V 2 C-NSs to promote plant growth and biosafety and its molecular mechanism of inducing plant resistance to Ralstonia solanacearum ( R. solanacearum ) were investigated. The results showed that V 2 C-NSs could increase plant fresh (or dry) weight, promote ROS accumulation, activate plant defense enzymes, and upregulate ethylene (ET) and jasmonic acid (JA) synthesis as well as the expression of ET/JA-responsive genes. Interestingly, the MAPK signaling pathway, biosynthesis of henylpropanoid and flavonoid were also activated, but the salicylic acid biosynthetic pathway was deactivated. Thus, V 2 C-NSs likely induced plant resistance to R. solanacearum via the ET/JA pathway. Furthermore, foliar application of V 2 C-NSs could delay occurrence of tobacco bacterial wilt, while the control efficiency reached 65.52 % nine days post-inoculation (dpi), followed by 57.00 % and 52.99 % at 11 dpi and 13 dpi, respectively, which were significantly greater than the control benzothiadiazole (BTH). Moreover, the biosafety of V 2 C-NSs was evaluated using tobacco seeds (Yunyan87), bacteria and earthworms. This study suggests that V 2 C-NSs can potentially be used as an environmental-friendly plant resistance inducer for controlling bacterial wilt diseases in sustainable crop protection.