Study On The Insect Chitosan(cts)-induced Effect Of Disease-resistance To Colletotrichum Gloeosporioides And The Biochemical Mechanisms

Camellia oleifera anthracnose is one of the major diseases in China's Camellia producing areas. It occurs broadly and causes serious drop in buds and leaves, sometimes resulting in the death of the tree. So strengthen control for Camellia oleifera anthracnose is very important. Some elicitors stimulate plants and then cause the defense system of plant, which can result in resistance to subsequent infection, this is induced resistance. For its advantage, such as safety, broad spectrum disease control, it has been paid attention for a long time. So the resistance induced by CTS (Chitosan prepared from Dendrolimus punctatus) against anthracnose of Camellia oleifera and relative biochenmical mechanisms were studied systemically in this paper.The result as follows:(1) The Resistance Induced by CTS against anthracnose of Camellia oleifera. The effect of antibacterial activity indoor of different concentrations of CTS on Colletotrichum gloeosporioides and induced resistant to the diease of Camellia oleifera was determined. The results indicated that CTS(0～1mg/ml) had no direct inhibition to spore germination and Colletotrichum gloeosporioides mycelia growth. Spraying 0～1mg/ml CTS could induce resistance to anthracnose of camellia oleiferas, treated with CTS 0.5 mg/ml, the best control efficiency was 74.33%. Local and systemic resistance to anthracnose of Camellia oleifera was induced when the plant was sprayed by CTS solutions.(2) The optimum protocol for CTS inducing Camellia oleifera against anthracnose was established. The optimum induced method, as well; the best induced intervals and continue time was studied. The results showed that the optimum induced method was the combination of pouring root and spraying leaves, the best interval was 5d and the efficiency of CTS could reach 15d. And the inducing effects between different varieties appear significant differences. The field experimental results show that control effect is 64.52% and significantly higher than carbendazim, so it has a broad application prospect.(3) The biochemical mechanism of CTS inducing Camellia oleifera against anthracnose. The content of protective enzymes and matters related to disease resistance was studied. The results showed that the activity of POD, PPO, PAL and SOD of Camellia oleifera leaves treated with CTS at the concentration of 0.5mg/ml was higher than that of the untreated ones. The peak activity of POD, PPO, PAL and SOD occurred at the 5th day, the 7th day, the 5th day and the 5th day with the maximum 26.7 (△OD/g·min),26.3 (0.001△OD/g·s),16.5 (0.01△OD/g·min),82.3 (inhibitory rate/g) respectively.Active oxygen species (AOX) in Camellia oleifera leaves after the induction of CTS was increased at the first day by 84.6% higher than that of control, and declined quickly after the second day.The content of malefic dialdenyde could be decreases in camellia leaves after CTS extract induction. And the expression of pathogenesis-related proteins and the content of malefic dialdenyde could be induced in camellia leaves after CTS extract induction. The quantity of soluble protein in the leaf treated by CTS extract and challenged inoculation with Colletotrichum gloeosporioides was higher than that in the leaves only treated by CTS extract.