Application of Cold Atmospheric Pressure Plasma Jet Results in Achievement of Universal Antibacterial Properties on Various Plant Seeds

In view of a constant growth in the human population on Earth, the provision of a necessary amount of high-quality food looks challenging. As over 10% of the crop yields are annually lost due to the presence of phytopathogens, the development of novel, eco-friendly methods of pest eradication might contribute to avoiding nutritional shortages. Here, we propose a controlled application of cold atmospheric pressure plasma (CAPP) generated in the form of an atmospheric pressure plasma jet (APPJ), for which we conducted multivariate optimization of the working parameters with the use of the design of experiments (DoE) in addition to the response surface methodology (RSM). After estimating the optimal operating conditions of APPJ, we determined the inactivation rates caused by 2 min CAPP exposure towards bacterial phytopathogens from three species Dickeya solani, Pectobacterium atrosepticum and Pectobacterium carotovorum artificially inoculated on the surface of plant seeds from four species. Logarithmic reductions, as a key result of this work, were enclosed in the range of 1.61-4.95 in the case of Cucumis sativus, Pisum sativum, and Vigna radiata, while for the bacteria-inoculated Zea mays seeds, lower antibacterial properties of APPJ equaling 0.86-1.12 logs were noted. The herein applied exposure to APPJ did not reveal any statistically significant detrimental effects on the germination of plant seeds, seed coat integrity, or early plant growth. Even plant growth promotion by 20.96% was observed for the APPJ-exposed Zea mays seeds. By applying colorimetric assays and optical emission spectrometry (OES), we determined the oxidative potential in addition to identifying the reactive oxygen species (ROS) center dot OH, center dot HO2, center dot O2-, O3, and 1O2 and the reactive nitrogen species (RNS) N, NO2, and NO3 responsible for the antibacterial properties of APPJ. In summary, universal antiphytopathogenic properties of the APPJ treatment reached due to proper optimization of the working conditions were revealed against three bacterial strains from the family Pectobacteriaceae inoculated on the seeds from diverse plant species. The data presented herein may contribute to future development of the plasma agriculture field and provide alternatives to pesticides or the prevention-based control methods towards plant pathogenic bacteria.