IIB   20738
INSTITUTO DE INVESTIGACIONES BIOLOGICAS
Unidad Ejecutora - UE
artículos
Título:
Evidence on antimicrobial properties and mode of action of a chitosan obtained from crustacean exoskeletons on Pseudomonas syringae pv. tomato DC3000
Autor/es:
A. Y. MANSILLA; J.R. MENDIETA; L. ALBERTENGO; M. S. RODRÍGUEZ; A. DEBBAUDT; A. ZUÑIGA; C. CASALONGUÉ
Revista:
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2013 vol. 97 p. 6957 - 6966
ISSN:
0175-7598
Resumen:
AbstractPseudomonas syringaepv.tomato DC3000 (Pto
DC3000) causes bacterial speck of tomato, a widely spread
disease that causes significant economical losses worldwide.
It is representative of many bacterial plant diseases for which
effective controls are still needed. Despite the antimicrobial
properties of chitosan has been previously described in phy-topathogenic fungi, its action on bacteria is still poorly ex-plored. In this work, we report that the chitosan isolated from
shrimp exoskeletons (70 kDa and 78 % deacetylation degree)
exerts cell damage onPtoDC3000. Chitosan inhibitedPto
DC3000 bacterial growth depending on its concentration,
medium-pH, and presence of metal ion (Mg
+2
). Biochemical
and cellular changes resulting in cell aggregation and impaired
bacterial growth were also viewed. In vivo studies using
fluorescent probes showed cell aggregation, increase in mem-brane permeability, and cell death, suggesting the chitosan
antibacterial activity is due to its interaction as a polycation
withPtoDC3000 membranes. Transmission electron micro-scopic analysis revealed that chitosan also causedmorpholog-ical changes and damage in bacterial surfaces. Also, the dis-ease incidence in tomato inoculated withPtoDC3000 was
significantly reduced in chitosan pretreated seedlings, reveal-ing a promising action of chitosan as nontoxic biopesticide in
tomato plants. Indeed, a wider comprehensive knowledge of
the mechanism of action of chitosan in phytopathogenic bac-terial cells will increase the chances of its successful applica-tion to the control of spread disease in plants