The role of Xanthomonas citri subsp. citri adhesin Fhab in its interaction with plants.

GARAVAGLIA, BS; OTTADO, J.; GOTTIG, N.

Rosario

Congreso; L Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular.; 2014

SAIB

The filamentous hemagglutinin-like protein adhesin, FhaB, of Xanthomonas citri subsp. citri (X. citri) is involved in virulence, adherence, leaf surface attachment and biofilm formation of this citrus pathogen. With the aim to study if FhaB protein is able to induce some changes in plant responses, we expressed different FhaB regions (AR1, AR2 and AR3) because FhaB is a 4,753 amino acids protein. The purified recombinant FhaB regions were infiltrated into pepper, tomato and citrus leaves and the appearance of chlorotic and necrotic lesions was observed. Cell death and callose deposition monitored by DAB and aniline blue staining, respectively showed significant increases in tissues treated with AR1, AR2 and AR3 compared to the control, demonstrating that plants can recognize these FhaB regions. To analyze genes involved in the innate immunity, oxidative stress and defense responses, citrus and tomato leaves were infiltrated with these regions. Quantitative RT-PCR assays showed that the three regions were able to induce the expression of genes involved in defense or resistance responses in plants. Particularly, in tomato plants genes involved in plant basal immune responses were significantly induced. Altogether these results indicate that X. citri FhaB can be recognized by plants and this triggers the activation of plant defense responses.