Surface Dielectric Barrier Discharge plasma: a suitable measure against fungal plant pathogens

Abstract

Fungal diseases seriously affect agricultural production and the food industry. Crop protection is usually achieved by synthetic fungicides, therefore more sustainable and innovative technologies are increasingly required. the atmospheric pressure low-temperature plasma is a novel suitable measure. We report on the effect of plasma treatment on phytopathogenic fungi causing quantitative and qualitative losses of products both in the field and postharvest. We focus our attention on the in vitro direct inhibitory effect of non-contact Surface Dielectric Barrier Discharge on conidia germination of Botrytis cinerea, Monilinia fructicola, Aspergillus carbonarius and Alternaria alternata. A few minutes of treatment was required to completely inactivate the fungi on an artificial medium. Morphological analysis of spores by Scanning electron Microscopy suggests that the main mechanism is plasma etching due to Reactive oxygen Species or UV radiation. Spectroscopic analysis of plasma generated in humid air gives the hint that the rotational temperature of gas should not play a relevant role being very close to room temperature. In vivo experiments on artificially inoculated cherry fruits demonstrated that inactivation of fungal spores by the direct inhibitory effect of plasma extend their shelf life. Pretreatment of fruits before inoculation improve the resistance to infections maybe by activating defense responses in plant tissues.

Effects of non‐thermal plasma technology on Diaporthe longicolla cultures and mechanisms involved

“…According to Panngom et al ., 54 cellular damage after high doses of plasma is usually accompanied by disintegration of organelles and DNA fragmentation. Also, it is well known that cell membrane lipids and proteins are primary targets of oxidation, so fungal exposition to the oxidative compounds of NTP may alter overall membrane properties and lead to cellular destruction 53 . In our work, the analysis of DNA integrity employing gel electrophoresis suggested the degradation of fungal DNA in exposed colonies (data not shown).…”

“…Also, it is well known that cell membrane lipids and proteins are primary targets of oxidation, so fungal exposition to the oxidative compounds of NTP may alter overall membrane properties and lead to cellular destruction. 53 In our work, the analysis of DNA integrity employing gel electrophoresis suggested the degradation of fungal DNA in exposed colonies (data not shown). According to Šimončicová et al, 20 DNA fragmentation can occur directly by oxidation of deoxyribose or indirectly by interruption of the repair process of the oxidized bases.…”

“…57 The reduction in conidial germination observed in our research agrees with other authors who also studied the effects of NTP on spore viability of different phytopathogens. 21,53,58,59 According to Ambrico et al, 53 NTP is effective against a great variety of fungal conidia, reducing to undetectable levels their germinability when placed on the surface of artificial media, indicating that plasma treatment can act directly on fungal spores due to the combined effect of active chemical species (ROS and RNS) and UV lights. The damage caused by NTP treatments to fungal cell membranes was demonstrated before, through the quantification of MDA content in colonies.…”

Impact of Corona Discharge on Aspergillus Niger Spores And Cyathus Olla Mycelium Growth

“…The first area is the plasmainduced destruction of the spores and fungi for the disinfection of buildings, people, or plants. The second area is the enhancement of the mycelium growth rate via the cell stimulation or enrichment of the fungal growth environment with the plasma products [1][2][3][4][5][6][7][8][9].…”

Piezoelectric Direct Discharge: Devices and Applications

“…Control of fungal plant pathogens [136] (e.g., Aspergillus flavus by surface barrier discharge [137]).…”