Antifungal activity of oligochitosan against Phytophthora capsici and other plant pathogenic fungi in vitro
Xu. J Zhao. X Han. X Du. Y
Pesticide Biochemistry and Physiology ; 2007 [Vol.87] Pages:220-228
Abstract
Antifungal activity of oligochitosan against nine phytopathogens was investigated in vitro. Oligochitosan was more eVective than chitosan in inhibiting mycelial growth of Phytophthora capsici and its inhibition on diVerent stages in life cycle of P. capsici was observed. Rupture of released zoospores induced by oligochitosan was reduced by addition of 100mM glucose. The eVects of oligochitosan on mycelial growth and zoospore release, but not zoospore rupture, were reduced largely when pH value was above 7. The ultrastructural study showed that oligochitosan caused distortion and disruption of most vacuoles, thickening of plasmalemma, and appearance of unique tubular materials. Plasmalemmasomes in hyphal tip cells were not found in the presence of oligochitosan. These results suggest polycationic nature of oligochitosan contributes only partly to its antifungal activity and multiple modes of action of oligochitosan exist including the disruption of endomembrane system.
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