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 V2C MXene nanosheets have been widely studied in the field of nanomedicine and biomaterials. However, few studies have shown has direct effects of V2C-NSs on crop protection and induces plant resistance to disease. In this study, V2C-NSs were first prepared by artificial synthesis and characterized, and the resulting material displayed an excellent Tyndall effect. The ability of V2C-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 V2C-NSs could increase plant fresh (or dry) weight, promote ROS accumulation, activate plant defense enzymes, and upregulate ethylene and jasmonic acid 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, V2C-NSs likely induced plant resistance to R. solanacearum via the ET/JA pathway. Furthermore, foliar application of V2C-NSs could delay occurrence of tobacco bacterial wilt, while the control efficiency reached 65.52% nine days post-inoculation followed by 57.00% and 52.99% at 11 and 13 dpi, respectively, which were significantly greater than the control benzothiadiazole . Moreover, the biosafety of V2C-NSs was evaluated using tobacco seeds, bacteria and earthworms. This study suggests that V2C-NSs can potentially be used as an environmental-friendly plant resistance inducer for controlling bacterial wilt diseases in sustainable crop protection.