Biological Activity And Mechanism Of MCA On Plant Disease Control

MCA is a derivative of cinnamaldehyde extracted from the preparation of natural flavor cinnamon.It shows good biological activity and stability.In order to provide theoretical basis for its application in plant disease control,the ability and mechanism of MCA in controlling plant disease were studied.The methods of plate culture,Oxford plate assay system and filter paper were used respectively to determine the antimicrobial activity of MCA.The results showed that MCA had significant inhibition aginst mastigomycotina,ascomycotina and euteromycotina. MCA had obviously anti-bacteria activity to Ralstonia solanacearum in high concentration. The study also found that MCA could inhibit tobacco mosaic virus(TMV)infecting to tobacco leaf.The field efficacy trials of MCA showed relatively good and lasting control of Rhizoctonia solani.In the same concentration,there was no significant difference between the effect of MCA and Jinggangmycin in field efficacy,and its effect could last for over 14 days.The result of experiment also showed that MCA had excellent control effect on Pseudoperonospora cubensis and Sphaerotheca fuliginea.The MCA had tremendous development potential.Taking Rhizoctonia solani and Sphaerotheca fuliginea as objects of study,the antagonistic mechanism was studied at the level of cellular morphology and cellular physiology.In order to investigate the antifungal effects of MCA on these two phytopathogenic funguses,the control and treated mycelial cells were observed by scanning electron microscope(SEM),transmission electron microscope(TEM)and laser scanning confocal microscope(LSCM).The results showed that mechanisms of MCA were multi-faceted as follows:the cell wall of mycelia was thickened,cellular membrane permeability was strengthened,the number of mitochondrion was increased,the configuration of mycelial cells treated with MCA was destroyed,fluorescence intensity of the treated cells and that of control group was different significantly.It indicated that the synthesis of DNA,the mitochondrial membrane potential and the ROS level of Rhizoctonia solani hyphae were greatly influenced by MCA. The analysis determination of Nicotiana glutinosa between pre-and post-treatment showed that the content of chlorophyll,total phenolics and flavonoids in Nicotiana glutinosa was significantly higher after treated by MCA.Taking rice as the object of study,we found that MCA could induce the chitinase and increase 1,3-glucanase activity to enhance the disease resistance of rice.We guess that MCA is a botanical fungicide which has development and application prospect.