The Effect Of Yeast And Chitosan Treatment On Structure With Colletotrichum Gloeosporioides Inoculation On Citrus Fruit

China is rich in citrus resource and Chongqing is one of the top ten major production areas.Citrus sinensis L.Osbeck ‘Jin Cheng447’ fruit is one of the most important citrus cultivars in autumn while C.sinensis L.Osbeck ‘Valencia Late’ in summer.During storage,the pathogen infection causes lots financial loss,especillay the anthranose caused by Colletotrichum gloeosporioides.Meanwhile,the unsuitable way of storage and transport way can cause many mechanical wound,which can make the fruit more sensitivity to infect pathogen.The previous study proved that 10⁸ cells/mL Pichia membranaefaciens and 0.01% chitosan can against C.gloeosporioides effectively,and can induce fruit resistance.However,there are less study about the cell structure during pathogen infection with treated by P.membranaefaciens and chitosan.On the other hand,the wound-healing process can produce after wound and exogenous treatment can promote wound-healing process,but there are less study on wound-healing of citrus,the effect of P.membranaefaciens and chitosan treatment,and the effect of wound-healing on pathogen infection.So the objective of this study was to evaluate the effect of chitosan and P.membranaefaciens on the cell structure of citrus fruit with C.gloeosporioides inoculation,meantime evaluate the effect of chitosan and P.membranaefaciens on anthracnose,wound-healing and cell wall structure on citrus fruit;the relationship between wound-healing and cell wall components.The main research findings were summarized as follows:（1）10⁸ cells/mL P.membranefaciens and 0.01% chitosan treatment could control the anthracnose effectively;（2）10⁸ cells/mL P.membranefaciens and 0.01% chitosan treatment could regulation ROS（H₂O₂,O-2）at the early stage of storage,increase the reactive oxygen species（ROS）content,as signal substances to induce defense system;at the end stage of storage,P.membranefaciens and chitosan treatment could decrease the ROS content,control the cell membrane damage（MDA and Relative leakage）;（3）10⁸ cells/mL P.membranefaciens and 0.01% chitosan treatment can increase PAL activity,promote the lignin accumulation;meanwhile decrease the PG,PME,CEL activity,slow down the degradation of pectin and cellulose;（4）wound-healing accompanied by the water loss and browning.10⁸ cells/mL P.membranefaciens and 0.01% chitosan treatment could enhance the wound-healing process,and during this process,cell wall composition accumulation.On the other hand,P.membranefaciens and chitosan treatment could destroy the flavedo tissues,and protect the albedo tissues and oil glands by scanning electron microscope（SEM）;（5）C.gloeosporioides can be controlled by the wound-healing and effect the wound-healing process,which is quickly accumulate lignin to control anthracnose.The ASP,cellulose have strong negative correlation with lignin,so we can predict that the effect of pathogen infection is outdistance the effect of wound-healing.On the other hand,P.membranefaciens and chitosan treatment could protect the flavedo tissues,the albedo tissues and oil glands by SEM.In conclusion,this study shows that the cell structure and tissue structure of citrus are destroyed after the C.gloeosporioides invasion,and during this process,the P.membranefaciens and chitosan treatment can maintain the cell structure and structure.