Xanthan is not essential for pathogenicity in citrus canker but contributes to<Emphasis Type="Italic"> Xanthomonas</Emphasis> epiphytic survival |
| |
Authors: | Germán Dunger Verónica M Relling María Laura Tondo Máximo Barreras Luis Ielpi Elena G Orellano Jorgelina Ottado |
| |
Institution: | (1) Molecular Biology Division, IBR (Instituto de Biología Molecular y Celular de Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina;(2) Fundación Instituto Leloir, Avda. Patricias Argentinas 435, 1405 Buenos Aires, Argentina |
| |
Abstract: | Xanthan-deficient mutants of Xanthomonas axonopodis pv. citri, the bacterium responsible for citrus canker, were generated by deletion and marker exchange of the region encoding the carboxy-terminal
end of the first glycosyltransferase, GumD. Mutants of gumD did not produce xanthan and remained pathogenic in citrus plants to the same extent as wild-type bacteria. The kinetics of
appearance of initial symptoms, areas of plant material affected, and growth of bacteria inside plant tissue throughout the
disease process were similar for both wild-type and mutant inoculations. Moreover, exopolysaccharide deficiency did not impair
the ability of the bacteria to induce hypersensitive response on non-host plants. Apart from variations in phenotypic aspects,
no differences in growth or survival under different stress conditions were observed between the xanthan-deficient mutant
and wild-type bacteria. However, gumD mutants displayed impaired survival under oxidative stress during stationary phase as well as impaired epiphytic survival
on citrus leaves. Our results suggest that xanthan does not play an essential role in citrus canker at the initial stages
of infection or in the incompatible interactions between X. axonopodis pv. citri and non-host plants, but facilitates the maintenance of bacteria on the host plant, possibly improving the efficiency of
colonization of distant tissue. |
| |
Keywords: | Xanthomonas Citrus canker Xanthan |
本文献已被 PubMed SpringerLink 等数据库收录! |
|