Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) is a bacterial pathogen of tomato and of the model plants Arabidopsis and Nicotiana benthamiana (N. benthamiana). Like numerous Gram-negative bacterial pathogens of ...Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) is a bacterial pathogen of tomato and of the model plants Arabidopsis and Nicotiana benthamiana (N. benthamiana). Like numerous Gram-negative bacterial pathogens of animals and plants, Pst DC3000 exploits the conserved type III secretion system (TTSS) to deliver multiple virulence effectors directly into the host cells. Type III effectors (T3Es) collectively participate in causing disease, by mechanisms that are not well clarity. Elucidating the virulence function of individual effector is fundamental for understanding bacterial infection of plants. Here, we focused on studying one of these effectors, HopAA1-1, and analyzed its potential function and subcellular localization in N. benthamiana. Using an Agrobacterium-mediated transient expression system, we found that HopAA1-1 can trigger domain-dependent cell death in N. benthamiana. The observation using confocal microscopy showed that the YFP-tagged HopAA1-1 localizes to diverse cellular components containing nucleus, cytoplasm and cell membrane, which was demonstrated through immunoblot analysis of membrane fractionation and nuclear separation. Enforced HopAA1-1 subcellular localization, by tagging with a nuclear localization sequence (NLS) or a nuclear export sequence (NES), shows that HopAA1-1-induced cell death in N. benthamiana is suppressed in the nucleus but enhanced in the cytoplasm. Our research is lay a foundation for revealed the molecular pathogenesis of Pseudomonas syringae pv. tomato.展开更多
文摘Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) is a bacterial pathogen of tomato and of the model plants Arabidopsis and Nicotiana benthamiana (N. benthamiana). Like numerous Gram-negative bacterial pathogens of animals and plants, Pst DC3000 exploits the conserved type III secretion system (TTSS) to deliver multiple virulence effectors directly into the host cells. Type III effectors (T3Es) collectively participate in causing disease, by mechanisms that are not well clarity. Elucidating the virulence function of individual effector is fundamental for understanding bacterial infection of plants. Here, we focused on studying one of these effectors, HopAA1-1, and analyzed its potential function and subcellular localization in N. benthamiana. Using an Agrobacterium-mediated transient expression system, we found that HopAA1-1 can trigger domain-dependent cell death in N. benthamiana. The observation using confocal microscopy showed that the YFP-tagged HopAA1-1 localizes to diverse cellular components containing nucleus, cytoplasm and cell membrane, which was demonstrated through immunoblot analysis of membrane fractionation and nuclear separation. Enforced HopAA1-1 subcellular localization, by tagging with a nuclear localization sequence (NLS) or a nuclear export sequence (NES), shows that HopAA1-1-induced cell death in N. benthamiana is suppressed in the nucleus but enhanced in the cytoplasm. Our research is lay a foundation for revealed the molecular pathogenesis of Pseudomonas syringae pv. tomato.
