| Autor: |
Metz, Matthew, Dahlbeck, Douglas, Morales, Christina Q., Sady, Bassem Al, Clark, Eszter T., Staskawicz, Brian J. |
| Předmět: |
|
| Zdroj: |
Plant Journal; Mar2005, Vol. 41 Issue 6, p801-814, 14p |
| Abstrakt: |
Nicotiana benthamianaleaves display a visible plant cell death response when infiltrated with a high titer inoculum of the non-host pathogen,Xanthomonas campestrispv.vesicatoria(Xcv). This visual phenotype was used to identify overlapping cosmid clones from a genomic cosmid library constructed from theXcvstrain, GM98-38. Individual cosmid clones from theXcvlibrary were conjugated intoX. campestrispv.campestris(Xcc) and exconjugants were scored for an altered visual high titer inoculation response inN. benthamiana. The molecular characterization of the cosmid clones revealed that they contained a novel gene,xopX, that encodes a 74-kDa type III secretion system (TTSS) effector protein.Agrobacterium-mediated transient expression of XopX inN. benthamianadid not elicit the plant cell death response although detectable XopX protein was produced. Interestingly, the plant cell death response occurred when thexopX Agrobacterium-mediated transient expression construct was co-inoculated with strains of eitherXcvΔ xopXorXcc, both lackingxopX. The co-inoculation complementation of the plant cell death response also depends on whether theXanthomonasstrains contain an active TTSS. Transgenic 35S-xopX-expressingN. benthamianaplants also have the visible plant cell death response when inoculated with the non-xopX-expressing strainsXcvΔ xopXandXcc. Unexpectedly, transgenic 35S-xopX N. benthamianaplants displayed enhanced susceptibility to bacterial growth ofXccas well as other non-xopX-expressingXanthomonasandPseudomonasstrains. This result is also consistent with the increase in bacterial growth on wild typeN. benthamianaplants observed forXccwhen XopX is expressedin trans. Furthermore, XopX contributes to the virulence ofXcvon host pepper (Capsicum annuum) and tomato (Lycopersicum esculentum) plants. We propose that the XopX bacterial effector protein targets basic innate immunity in plants, resulting in enhanced plant disease susceptibility. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Plný text