A plant natriuretic peptide-like molecule of the pathogen Xanthomonas axonopodis pv. citri causes rapid changes in the proteome of its citrus host

GARAVAGLIA, B.S.; THOMAS, L.; ZIMARO, T.; GOTTIG, N.; DAURELIO, L. D.; NDIMBA, B.; ORELLANO, E; JORGELINA OTTADO; GEHRING, C.

BMC PLANT BIOLOGY

BIOMED CENTRAL LTD

Año: 2010 vol. 10 p. 51 - 51

1471-2229

AbstractBackground: Plant natriuretic peptides (PNPs) belong to a novel class of peptidic signaling molecules that sharesome structural similarity to the N-terminal domain of expansins and affect physiological processes such as waterand ion homeostasis at nano-molar concentrations. The citrus pathogen Xanthomonas axonopodis pv. citripossesses a PNP-like peptide (XacPNP) uniquely present in this bacteria. Previously we observed that the expressionof XacPNP is induced upon infection and that lesions produced in leaves infected with a XacPNP deletion mutantwere more necrotic and lead to earlier bacterial cell death, suggesting that the plant-like bacterial PNP enables theplant pathogen to modify host responses in order to create conditions favorable to its own survival.Results: Here we measured chlorophyll fluorescence parameters and water potential of citrus leaves infiltrated withrecombinant purified XacPNP and demonstrate that the peptide improves the physiological conditions of thetissue. Importantly, the proteomic analysis revealed that these responses are mirrored by rapid changes in the hostproteome that include the up-regulation of Rubisco activase, ATP synthase CF1 a subunit, maturase K, and a- andb-tubulin.Conclusions: We demonstrate that XacPNP induces changes in host photosynthesis at the level of proteinexpression and in photosynthetic efficiency in particular. Our findings suggest that the biotrophic pathogen canuse the plant-like hormone to modulate the host cellular environment and in particular host metabolism and thatsuch modulations weaken host defence.