Key Factors Of Photoactivated Pesticide Hypocrellin A Against Botrytis Cinerea

Hypocrellin A(HA), as the secondary metabolites of medicinal fungi Hypocrella bambusea and Shiraia bambusicola, is a good Perylenequinonoid photosensitizer in China. As a kind of phototherapy drug, HA has been developed and utilized major in medicine. But as the photoactivated pesticide, the research has just started.This paper adopts mycelium growth rate method to evaluate the inhibition rate of HA against Botrytis cinerea, base on the principle of quenching reactive oxygen to test the type of photodynamic action during the process of HA inhibit Botrytis cinerea; and applys the principle of capturing 1O2、Fenton reaction and Photochemical reaction of riboflavin to analyze the correlation between the yield of ROS and the inhibition rate of HA against Botrytis cinerea. The main results are as follows:1. With the increasing of light intensity, the higher concentration of HA results in increasing inhibition rate of HA against Botrytis cinerea, the inhibitoion rate of HA under light condition is significant different with the control group that without HA. While light intensity is 12000 Lx, the inhibition rate of 40 mg.L-1 HA against Botrytis cinerea can reach 65.15%, we conclude that light has important effects on inhibitory activity of HA.2. After add mannitol、ascorbic acid and histidine and cultured under lihgt, the inhibition rate of HA against Botrytis cinerea significantly reduce, compares with the control group, this indicates the inhibitiory activity of HA is caused by ROS which produced in photodynamic action. After adding histidine, the inhibition rate of HA against Botrytis cinerea is most significant differenct compares to control group. This suggests that Type I and Type II play combined effect during the process of HA against Botrytis cinerea, but Type II is more important.3. The inhibition rate of HA against Botrytis cinerea increased with raising the yield of 1O2. There are significant positive correlation at 0.05 level between the yield of 1O2 of HA and its inhibition rate against Botrytis cinerea, and the regression equation is Y= 0.703X+0.117, R2=0.986. The result show that 1O2 as the key factor plays a extremely role in the process of HA inhibit Botrytis cinerea..4. The inhibition rate of.OH against Botrytis cinerea increased with raising the concentration of fenton reagent. There are significant positive correlation at 0.05 level between the yield of.OH and its inhibition rate against Botrytis cinerea, and the regression equation is Y= 0.0022X+0.005,R2=0.9101. The result show that.OH as the key factor plays a extremely role in the process of HA inhibit Botrytis cinerea.5. The inhibition rate of O2.- against Botrytis cinerea increased with raising the concentration of riboflavin. There are significant positive correlation at 0.05 level between the yield of O2.- and its inhibition rate against Botrytis cinerea, and the regression equation is Y= 0.77X+0.045,R2=0.934. The result show that O2.- as the key factor plays a extremely role in the process of HA inhibit Botrytis cinerea.6. The optimal regression model has been attained by the method of stepwise regression, the regression equation is Y=0.0559+ 0.8145 X1 + 0.002 X2 +0.7384X3, R2=0.9619.(X1: the yield of 1O2, X2: the yield of.OH, X3: the yield of O2.-)The results reveal that the partial correlationcoefficient of 1O2 is the largest. We can see 1O2 is the most critical factor in the process of inhibiting Botrytis cinerea by HA, followed by O2.-, and.OH came in.In this study, the key factor of inhibiting Botrytis cinerea by HA is firstly reported, the results are useful in developing green and efficient biological pesticide for HA to provide theoretical basis.