Synthesis and effects of the selective oxidation of chitosan in induced disease resistance against Botrytis cinerea.

Plant fungal diseases can lead to yield reduction and quality degradation in crops, which usually cause serious economic losses. Additionally, chemical fungicides used in the prevention and control of plant diseases are increasingly restricted due to resistance development and high toxicity. Therefore, biogenic fungicides such as chitosan with low toxicity and good biocompatibility are receiving increasing attention. This study found that the acid swelling chitosan pretreatment method can accelerate the rate of the specific oxidation of chitosan catalyzed by the TEMPO-NaBr-NaOCl system. This study proved that OCTS induces plant disease resistance, and the control efficiencies achieved in protection and treatment experiments against Botrytis cinerea were 80.6 % and 83.4 %, respectively, at 400 μg/mL OCTS. In addition, OCTS can promote plant growth and enhance plant defense enzyme activities. This research has realized a forward-looking exploration of the application of OCTS in the agricultural field.