Antiviral Effects of the Liquid Culture, Cell Free Supernatants and Extracellular Products from Serratia marcescens subsp. marcescens against Watermelon Mosaic Virus (WMV)

THIS STUDY was to specify the potential antiviral action of Serratia marcescens subsp. marcescens and its extracellular products against watermelon mosaic virus (WMV). The highest level of protection observed occurred in experiments, where bacteria were mixed with the virus in vitro before inoculation, resulting in gave 100% viral inhibition. S. marcescens significantly improved (p< 0.05) several growth parameters in all experiments compared to viral control. The highest level of virus inhibition obtained when a mixture of all compounds extracted and purified from S. marcescens subsp. marcescens was applied to cucumber plants reducing infection by 95% . The results of RT-PCR showed that in vitro liquid bacterial culture treatment and applied 24 hr after virus inoculation treatment highly reduced the accumulation of WMV in treated plant leaves . The usage of S. marcescens in vitro and in vivo led to increasing in total protein, polyphenoloxidase, and phenolic compounds compared to viral-infected and healthy controls, while reducing glutathione oxidase. S. marcescens and its metabolic products found in culture filtrates show promise as an effective biocontrol agent for WMV infection in plants and appear to promote plant growth even in the absence of virus