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

Abstract

New biopolymer oligochitosan (OCS) and OCS/nanosilica (OCS/nSiO2) 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), nSiO2 (60 mg l−1) and OCS/nSiO2 (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/nSiO2 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 nSiO2, OCS or OCS/nSiO2 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. Functional oligochitosan-nanosilica (OCS/nSiO2) hybrid material is likely to be considered as natural vaccine for the growth and disease resistance of the plants. Study on hybrid material from low-cost and waste products such as OCS from chitosan and chitin, and nSiO2 from rice husk is likely to create a novel material with special synergistic effect. The plants treated with OCS/nSiO2 were not completely diseased by Colletotrichum sp. The biomass, the length, the chlorophyll content of the plants treated with OCS, nSiO2 or OCS/nSiO2 were higher than those of the control plants.