Functionalized carbon nano-enabled plant ROS signal engineering for growth / defense balance

The reactive oxygen species (ROS) wave plays a crucial role as an early systemic signal in nearly all environmental response pathways. Engineering on ROS signaling may be a promising strategy to modulate plant systemic acquired acclimation and systemic acquired resistance. Recently, artificial designed materials mimicking signal transduction components have attracted attention to improve plant immunity and stress acclimation. Here, we report the bioengineering of functional carbon nanoparticles (FCN) through their regulation on ROS signaling. FCN with a C:O atom ratio of 1:2.2 were synthesized by low voltage electrolysis with graphite and carboxyl were the main oxygen-containing groups on the surface of sp2 carbon core. The active redox properties resulting from the carboxyl–rich modification provided FCN superior ROS-triggering effects compared to other carbon nanoparticles with similar core structures but different types and quantities of surface modifications. Moreover, the ROS induced by FCN were quickly scavenged to homeostasis without causing accumulation and then leading to oxidative stress. The findings from transcriptional footprinting in Arabidopsis's genes revealed a typical and quick ROS signal transduction events and also the regulation of stress responses and adaptions to biotic and abiotic stresses. In addition, the application of FCN to roots have been shown to promote the growth and development of Arabidopsis, rice and wheat, and also the yields particularly when suffering stresses. In summary, our findings confirmed that the ROS burst triggered by FCN modulated the balance between growth and defense through transcriptome reprogramming. It indicates that nano-enabled plant engineering for ROS can provide an economical and efficient way to promote the crops yields, especially under stress conditions.