New oligochitosan-nanosilica hybrid materials: preparation and application on chili plants for resistance to anthracnose disease and growth enhancement

New biopolymer oligochitosan (OCS) and OCS/nanosilica (OCS/nSiO(2)) hybrid materials with remarkable synergistic effects are likely to be considered natural vaccines for the growth and disease resistance of plants. This study indicated that OCS (50 mg l(-1)), nSiO(2) (60 mg l(-1)) and OCS/nSiO(2) (50: 50 mg l(-1): mg l(-1)) not only created effective anti-fungal activity in chili plants but also enhanced their growth, even when the plants were infected with Colletotrichum sp. After fungal infection, the disease incidence of the control plants increased to 50.3% (after 14 days), 75.7% (after 21 days) and 100% (after 35 days). However, the plants treated with OCS/nSiO(2) were without disease, even when they have been infected by Colletotrichum sp. during the 35-day investigation. The fresh weight of shoots and roots, shoot length and chlorophyll content of the plants treated with nSiO(2), OCS or OCS/nSiO(2) hybrid material were higher than those of the control plants. These materials could be considered potential biotic elicitors that not only prevent anthracnose disease but also effectively promote plant growth.