A human pathogenic bacteriumShigellaproliferates in the plant through the adoption of type III effectors for Shigellosis

Abstract

AbstractHuman enteropathogenic bacteria has been reported to be transmitted by fresh vegitables.Shigella, which infects primates, is reportedly transmitted by fresh vegetables; however, its molecular interactions with plants have not been elucidated. Here, we show that fourShigellastrains,S. boydii(S. b),S. sonnei,S. flexneri2a (S. f2a), andS. flexneri5a (S. f5a), proliferated at different levels inArabidopsis thaliana. Microscopic studies revealed that these bacteria were present inside leaves and damaged plant cells. Green fluorescent protein (GFP)-taggedS. bandS. f5a colonized in leaves only, andS. f2a colonized both leaves and roots. Using mutants lacking type III secretion systems (T3SS), we found that T3SS ofShigellathat regulate the pathogenesis of Shigellosis in humans also play a central role in proliferation inArabidopsis.Strikingly, the immunosuppressive activity of two T3S effectors, OspF and OspG, were needed for the proliferation ofShigellainArabidopsis. Of note, delivery of OspF or OspG effectors inside of plant cells uponShigellainoculation was confirmed by using a split GFP system, respectively. These findings demonstrate that the human pathogenShigellacan proliferate in plants by adoption of immunosuppressive machinery for its original host human.