We investigated whether the co-occurrence of phytopathogens ( Clavibacter michiganensis  subsp.  michiganensis [ Cmm ] and  Xanthomonas gardneri  [ Xg ]) frequently encountered in tomato production and  Salmonella   enterica  subsp.  enterica  serotype Typhimurium (JSG626) affects the persistence of these pathogens in tomato plant tissues during the early stages of plant growth .  We observed that  Cmm  increased the persistence of  Salmonella  Typhimurium JSG626 (up to 1.8-log CFU/plant at 21 days post-inoculation; DPI) from co-inoculated tomato plants compared to plants inoculated with  S.  Typhimurium JSG626 alone (P<0.05).  Xg  had no effect on  S.  Typhimurium JSG626 persistence  in planta . The increased persistence of  S.  Typhimurium JSG626 was also observed when it was inoculated seven days after  Cmm  inoculation of the same plant tissues (P<0.05). On the other hand,  S.  Typhimurium JSG626 reduced the population of both  Cmm  and  Xg  (up to 1.5-log CFU/plant at 21DPI; P<0.05) in co-inoculated plants group compared to plants inoculated with  Cmm  or  Xg  alone. Further, the  Xg  population increased (1.16-log CFU/plant at 21DPI; P<0.05) when  S.  Typhimurium JSG626 was inoculated seven days after  Xg  inoculation compared to plants inoculated with  Xg  alone. Our findings demonstrate that the type of phytopathogen present in the phyllosphere and inoculation time influence the persistence of  S.  Typhimurium JSG626 and its interactions with phytopathogens co-colonized  in planta . Further,  Salmonella  seems to reduce the phytopathogen load in planta , while  Cmm  enhances the persistence of  Salmonella  from the co-inoculated plant tissues; however, further investigations are needed to understand mechanisms behind these interactions.

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