Role Of 1-Octen-3-ol On Inhibiting Postharvest Diseases Of Peach Fruit

Pathogenic fungi infection is one of the important causes of postharvest losses of peach fruit.Therefore,it is extremely important to seek a safe and effective method to control the main fungal diseases of postharvest peach fruit.1-Octen-3-ol is a volatile compound widely existed in fungi and some plants,which could participate in the signal transduction between organisms.1-Octen-3-ol has been included in food additives,but there are few studies on its role in controlling postharvest diseases of fruit and vegetables.In this study,the peach fruit was used as the material,and fumigation with 1-octen-3-ol was used to explore its effects on the main fungal diseases of postharvest peach fruit both in the enhancement of fruit disease resistance and fungistasis in vitro.Furthermore,1-octen-3-ol sustained-release materials were selected to facilitate its application in the postharvest storage of peach fruit.The details are as follows:（1）Through the isolation and identification of pathogens on peach fruit with infectious diseases in the main producing areas of Shandong Province,it was found that brown rot and soft rot caused by Monilinia fructicola and Rhizopus stolonifer respectively are the major diseases on peach fruit.1-Octen-3-ol fumigation treatment could control the natural incidence of postharvest peach fruit with certain concentration dependence.But high concentration of1-Octen-3-ol could easily cause damage to the peach fruit.（2）When the spatial concentration of 1-octen-3-ol was 55.80μg m L^-1,the control effect on postharvest diseases of peach fruit was the best,and the disease incidence and lesion diameter of peach fruit inoculated with M.fructicola and R.stolonifer could be significantly reduced（P<0.05）.（3）1-Octen-3-ol fumigation treatment could induce the enzyme activity of CHI,GLU and relative genes expression in salicylic acid（SA）pathway,such as ICS1,NPR1,TGA1 and PR1 in peach fruit,which could mediate systemic acquired resistance（SAR）,thereby improving the resistance of peach fruit against M.fructicola infection.For peach fruit inoculated with R.stolonifer,1-octen-3-ol fumigation treatment could also significantly（P<0.05）up-regulate the CHI and GLU enzyme activity related to the SA disease resistance pathway,as well as the expression levels of SAR marker genes NPR1 and PR1,which was speculated that the process of 1-octen-3-ol fumigation regulating peach fruit resistance to soft rot is similar to that of brown rot.（4）In vitro,1-octen-3-ol fumigation treatment could significantly inhibit the hyphae extension of M.fructicola and R.stolonifer on PDA plate（P<0.05）,destroy the microstructure of mycelium,reduce ergosterol content,as well as induce the expression of Mfcut1,Mfcyp51,Mfabc1,Mfaox1 in M.fructicola and Rscut1α,Rseg1 in R.stolonifer.1-Octen-3-ol could also inhibit the spore germination rate,and lead to spore apoptosis by reducing mitochondrial membrane potential（MMP）significantly to increase the level of reactive oxygen species（ROS）in spores（P<0.05）.（5）The compound gels of 2%agar,2%curdlan,1%agar mixed 1%curdlan was prepared to screening the suitable materials,and 1-octen-3-ol was added to investigate the sustained-release effect.It was found that the 2%agar gel containing 1-octen-3-ol had the best inhibitory effect on the mycelial growth of M.fructicola and R.stolonifer in vitro.Due to hydrogen bond and other internal cohesive forces,there was strong thermal stability of the compound gel with 1-octen-3-ol,and the loose and porous structure formed inside improved the sustained release of 1-octen-3-ol.Compared with single ingredient gel,the release effect of compound gel could significantly control the spread of brown rot and soft rot of postharvest peach fruit（P<0.05）.