Inhibitory effect of UVC against Pseudomonas spp. -causing sugar beet spoilage

UVC is known to have good bacteriostatic properties. However, the mechanism of bacterial inhibition of UVC against Pseudomonas was lacking, so it was comprehensively studied from several aspects. Through phenotyping experiments combined with transcriptome differential expression gene validation, the following mechanisms of UVC inactivation in bacteria were proposed: (1) UVC interferes with purine synthesis and DNA replication by down-regulating the nrdD , nrdA , nrdB , yagT , yagS and yagR genes, leading to impaired DNA synthesis in bacteria; (2) UVC reacts with macromolecules such as proteins in the bacterial cell wall/membrane that down-regulate genes related to cell wall synthesis and osmotic pressure homeostasis ( waac , galu , udg , and murQ ), resulting in damage to bacterial cell wall/membrane; (3) UVC can generate ROS in bacteria and disrupt the antioxidant system, making accumulation of ROS, which induces oxidative stress; (4) UVC, by up-regulating eleven genes related to oxidative phosphorylation and TCA cycling leading to disruption of energy metabolism, which in turn causes bacterial death. In summary, this study provides a solution with application potential to address the problem of reduced sucrose content in sugar beet storage. • The 5KJ/m 2 UVC inhibited P. frederiksbergensis XJ-4 by 99.30%. • UVC could generate ROS, damage energy metabolism, and interfere with • DNA synthesis. • In vivo , UVC inhibited 92.67% of P. frederiksbergensis XJ-4. • Reductions in AI, SS-I and NI enzyme activities maintain sugar beet quality.