INVESTIGADORES
VOJNOV Adrian Alberto
congresos y reuniones científicas
Título:
Changes in the composition of xanthan affect its structure and its role as virulence factor of Xanthomonas campestris
Autor/es:
BIANCO MI; LAILA TOUM; YARYURA PM; MIELNICHUK N; ROESCHLIN R.A.; M. R. MARANO; ADRIÁN A. VOJNOV
Lugar:
Foz Iguazu
Reunión:
Congreso; 11th Congreso Internacional de Biología Molecular de Plantas (IPMB 2015); 2015
Resumen:
Xanthan is an important virulence factor of Xanthomonas that could be used as target in the development of control biotechnological strategies against these bacteria. Xanthan is composed by pentasaccharidic repetitive units substituted with acetyl and/or pyruvate groups. Our goal is to determine which component of the xanthan molecule is key for its function as virulence factor. We analyze four mutants of Xanthomonas campestris (Xcc) that produce xanthan modified in its composition and a xanthan-defective strain. In vitro assays showed that bacterial adhession decreased 20-35% in mutants that synthetized xanthan without acetyl (XcF, XcG) or pyruvate (XcL) groups, 55% in mutant that produced polytetrasaccharide (XcI), and 86% in the xanthan-defective strain. We observed differences between biofilms formed by all mutants. XcL formed a biofilm with similar thickness and biomass values than that formed by WT strain, but flatter, less heterogeneous, and more compact with low tendency to form micro-colonies and undefined channels. Similar results were observed in the biofilm formed by XcI. In Nicotiana benthamiana infections, XcL, XcI and Xc1231 failed in colonization of leaf tissue, while WT strain reached a severe infection. Pretreatment with xanthan synthesized by WT strain and with xanthan from XcF and XcG restored two to three orders the bacterial growth of all mutants, while pretreatment with xanthan from XcL and from XcI, restored only one order the bacterial growth in all cases. Altogether, these results suggest that pyruvate groups and terminal mannose are important to the role of xanthan in the virulence and pathogenicity of Xcc.