The Role And Mechanism Of Polyamines Involves In Methyl Jasmonate-regulated Postharvest Quality Retention Of Button Mushroom(Agaricus Bisporus)

Methyl jasminate(MeJA)is a naturally endogenous signal molecules in plants,play an important role in induced resistance of plants and fruit.Polyamines(PAs)as a growth regulator,are widely involved in the process of plant metabolism.It has been studied deeply that PAs are involved in the regulation of MeJA in plants,however,few studies have been done in the field of postharvest fruits and vegetables,especially in the field of edible fungi.In this study,Agaricus bisporus as the model of edible mushrooms which used to investigate the role and mechanism of PAs in the quality control of Agaricus bisporus regulated by MeJA.It is contribute to understand the postharvest preservation mechanism in edible fungus induced by MeJA.The major results of this research were as follows:Mushrooms were treated with 120 ?M DFMO and combination of 100 ?M MeJA,before storage at 4 ? for 21 d.The indexes related to quality and PAs content of fruit bodies in Agaricus bisporus were detected.Result showed,ODC activity was inhibited when DFMO application.Besides,which strongly attenuated effects of MeJA on decreasing cap opening,slowing the decline rate of soluble protein and total sugar,and accumulating total phenolics and flavonoids.DFMO pretreatment also counteracted MeJA effects on inhibiting polyphenol oxidase and lipoxygenase activities and malondialdehyde production,and stimulating superoxide dismutase and catalase activities.Furthermore,Put content in fruit bodies decreased remarkably when ODC-inhibited.In conclusion,the results indicate that ODC involves in postharvest quality retention that MeJA exerts on A.bisporus mushroom,and.Put content decreased may be the main reason leading to reduction in quality of mushroom.The content of PAs and amino acid,gene expression of PAs related have been detected in different tissues of fruit bodies.Result showed that Putrescine(Put)and spermidine(Spd)were mainly PAs exsisting in mushroom,wheras Spermine(Spm)content only in trace,only 0.4-1.1 ?mol g-1 FW.PAs content in different tissues have tissue specificity,Put content are highest in stipe,the conent of Spd and Spm higher than others.There is high correlation between Put content and ornithine content in pileipellis gill and inner cap.Different degree of correlation have been exsisting between Put content and gene expression of ODC?ARG?OAT?SPDS.The content of PAs and amino acid,gene expression and activities of PAs synthesis related have been detected in fruit bodies when treated by 100 ?M MeJA.Result showed MeJA vapor treatment increased the level of Put,Spd in fruit bodies during last storage,decreased contents of arginine and ornithine,promoted genes relative expression of AbODC,AbARG,AbOAT,AbSPDS,AbASL,AbASS in fruit bodies after storage days 9,increased activities of ODC,ARG and OAT in fruit bodies at last storage.In conclusion,MeJA treatment improved PAs accumulation in harvest bodies related to increased gene expression and activities of PAs synthesis related during storages.