Study On Inhibitory Activity And Mechanism Of Cleome Spinosa On Botrytis Cinerea In Strawberry

Strawberries are rich in nutrients,tender in tissue,and have a high water content,making them susceptible to infection by Botrytis cinerea,leading to decay and deterioration,decreased quality,shortened shelf life,and even loss of nutritional and commercial value,affecting the sales,processing,import and export trade of strawberries,and causing serious economic losses.Strawberry gray mold can occur in the field and post harvest,pesticides are usually used for control.However,chemical control poses a serious threat to human health due to a series of issues such as pesticide residues and environmental pollution.Therefore,developing efficient sterilization and preservation products and technologies that are safe,environmentally friendly,friendly to humans and the environment,and have good control effects on post harvest diseases is currently an urgent research topic to be solved.Our laboratory’s preliminary research found that Cleome spinosa and its 3 volatile substances have good inhibition effects on plant soil borne pathogens.However,there is no report on whether Cleome spinosa and its volatile substances have inhibitory effects on Botryis cinerea.Therefore,the inhibition activity and mechanism of Cleome spinosa and its three volatile substances against Botryis cinerea were studied.The results are as follows:1.The pathogens were isolated and purified from strawberry fruit s and finally was identified as Botrytis cinerea by pathogenicity test,morphology and molecular biology identification.2.The crushed materials of leaves,flowers,stems,and whole plants of Cleome spinosa have a significant inhibitory effect on Botrytis cinerea,and the inhibition rate increases with the increase of the dosage of Cleome spinosa;The inhibition effect of the whole plants is the best,followed by flowers,leaves,and stems.The inhibition rate of the 1.0 g/dish of the whole plant crushed materials of the Cleome spinosa against Botrytis cinerea were 97.51%,and that of the flowers,leaves,and stems were 89.29%,88.25%,and 81.47% respectively.3.Linalool,paeonol and teaspirane,the three volatile substances of Cleome spinosa,have a higher inhibitory effect on Botrytis cinerea through fumigation than through direct contact.The EC50 values of linalool,paeonol and teaspirane for fumigation inhibition were 0.96 μL/L,88.10μL/L and 4.93 μL/L.The EC50 values for linalool,paeonol and teaspirane for contact inhibition were 525.88 μL/L,652.35 μL/L,and 597.50 μL/L.4.The minimum inhibitory concentration(MIC)and minimum bacte ricidal concentration(MBC)of linalool against Botrytis cinerea are both 1.0 μL/m L;The MIC and MBC of paeonol and teaspirane against Botrytis cinerea was both 1.0 μL/m L and 2.0 μL/m L respectively.5.After fumigation with three volatile substances from th e Cleome spinosa to treat the Botrytis cinerea,scanning electron microscopy observed that the outer wall of the mycelium was damaged,fractured,and uneven in texture,with varying degrees of damage;The activities of SDH enzyme,MDH enzyme,and ATPase in mycelium decreased significantly,resulting in insufficient energy supply for mycelium growth and inability to convert respiratory metabolites;The extracellular conductivity increases and the cell contents leak out;The content of malondialdehyde significantly increases,the degree of membrane lipid peroxid ation intensifies,and the cytotoxicity of cells strengthens;The content of ergosterol decreased,the PI staining hyphae emitted visible red fluorescence,and the cell membrane function was damaged.6.After the three volatile substances were fumigated ag ainst Botrytis cinerea,the virulence Bc PDR1 gene and peroxidase Bccat A gene of Botrytis cinerea were significantly down regulated,the cell wall degrading enzyme Bcpg5 gene was significantly up regulated,and the mitotic protein Bc RAC gene was first significantly up regulated and then down regulated.7.After fumigating strawberry fruits with three volatile substances,the rate of fruit decay can be delayed,the shelf life can be extended,and the decrease rate of Vc content,soluble sugar,and soluble solid nutritional indicators in strawberry fruits and vegetables can be slowed down.