Preliminary Study On The Oligochitosan Induced Plant Resistance And Its Mechanisms

Oligochitosan prepared from enzymatic hydrolysis of deacetylated chitin was tested for its plant resistance induction activity against cotton Verticilium wilt and tobacco mosaic virus disease. Methods of plant pathology, biochemistry and molecular biology were applied to explore the mechanisms of oligochitosan induced resistance on suspended culture cells and/or seedlings of cotton, tobacco and strawberry. The results were listed as follows:Oligochitosan effectively induced the resistance of cotton and tobacco against cotton Verticilium blight and tobacco mosaic virus (TMV) disease, respectively. The effect greatly depended on concentration with the optimum concentration 50μg.ml^-1.Oligochitosan labeled with 2-aminoacidone (2-AMAC) binded directly outside on the cell membrane and cell wall of strawberry and tobacco cells. For the first time, we observed the binding process of 2-AMAC labeled oligochitosan to the cell walls and membrane of strawberry cells within 5 min by Cell Imaging System with Laser Induced Fluorescence Microscopy. It was further proved that binding of 2-AMAC labeled oligochitosan to plant cells was specific and reversible with laser scanning confocal microscopy (LSCM)Signal molecules H₂O₂ and NO could be induced by oligochitosan in epidermal tobacco cells. Oligochitosan and NO donor sodium nitroprusside...