Inactivation and inhibition of Botrytis cinerea by plasma-activated water long-lived species

The Botrytis cinerea represents a significant threat to the quality of fruits and vegetables, reducing grape yields by up to 50%. The use of chemicals for undifferentiated control poses food safety and environmental pollution risks. This work investigated the effects of long-lived species in plasma-activated water (PAW) on the survival of spores and the development of mycelium throughout the whole process of Botrytis cinerea propagation and infestation. Additionally, the contribution of long-lived species to inactivating and inhibiting Botrytis cinerea, as well as their action mechanism were quantitatively analyzed. The results demonstrated that the content of long-lived species in PAW reached its highest level after 30 min of plasma activation. The inactivation rate of spores and inhibition rate of mycelial growth reached 100% and 83.54%, respectively. It was found that the primary long-lived species responsible for inactivating spores and inhibiting mycelium are different. H₂O₂ is more effective for spore inactivation (56.83%), while H₂ is more efficient for mycelium inhibition (43.76%). Physiological analyses revealed that the two long-lived species, H₂O₂ and H₂, exhibit distinct pathways for spores inactivation. H₂O₂ primarily disrupts spore membranes, enhances permeability, and induces exocytosis of intracellular proteins, ultimately leading to spore inactivation. H⁺ mainly acts on cell wall tension, elevates intracellular levels of reactive oxygen species, induces oxidative stress, and impedes physiological metabolism, resulting in spore cell inactivation.