Research On Phenylpropanes Metabolism And Gene Expression Of Key Enzymes In Apricot Fruit By Salicylic Acid And Chitosan Oligosaccharide Treatment

In order to analyze the relationship between the regulation of phenylpropanoid metabolites, a key enzyme and disease resistance, as well as the expression of key genes involved in resistance molecules mechanism in apricots fruits treated by salicylic acid(SA), chitosan oligosaccharide(COS) treatment. Xinjiang apricot fruit(Saimaiti) were taken as the test materials in this paper. Postharvest disease control method combines molecular biology methods and modern chemical analysis instruments and other means were used to research the nature incidence,disease index, lesion diameter caused by Alternaria black spot, changes in key enzymes,genes and metabolites of the phenypropanoid metabolic pathway in apricots fruits induced by SA and COS treatment.Using quantitative real-time PCR to reveal the genes defense response to resist black spot of apricot fruit treated by SA and COS treatment, and analysis function of PAL, POD, C4 H and regulation mechanism in blackspot resistance.This study choose the best concentration of SA, COS treatment: 0.01g/L和0.50% on the basis of many research in our laboratory.One of the apartment apricots fruits treated by 0.01g/L SA and 0.5% COS solution were used to observe the natural incidence, the rest with damage inoculation were used to regularly measured the innoculation incidence, lesion diameter,the activity of PAL,POD,C4 H,4CL,the contents of lignin, flavonoids and the total phenol at 7th,14 th,21th,28 th,35th,42 th days. Using real-time quantitative PCR to determine the relative expression of PAL, POD genes, C4 H gene. The main results of the research are as follows:(1) The natural incidence, disease index and extension of lesion diameter in apricots fruits were significantly inhibited by SA and COS treatment. During the storage, incidence and lesion diameter of fruits treated by 0.01 g/ L SA was always lower than the incidence of 0.50% COS treatment.This indicated that the effect of disease control in SA treatment apricots fruits is superior to COS.(2) The activity of PAL, POD, C4 H, 4CL and contents of total lignin,phenols and flavonoids in apricots fruits could be significantly increased by SAtreatment, therefore,SA enhance the fruit resistance metabolism. COS treatment activated the PAL, POD and 4CL activity apricot fruit increased, but C4 H activity was inhibited. COS treatment can improve the content of lignin and total phenols fruit, but have no significant role in promoting the accumulation of flavonoids content.(3) The expression level of PAL gene were enhanced by SA and COS treatment, but SA treatment increase effect was stronger than COS, and SA ahead of the peakof the PAL gene expression. For POD gene expression studies showed that, SA and COS can promote gene expression POD apricot fruit, but the trend is different. The trend of POD gene expression by COS treatment showing first increased and then decreased, its maximum expression reached at 21 th day. The POD expression has been an upward trend throughout the storage period in SA processed apricots fruits, and with the extension of storage time, its expression level is gradually increasing. The regulation of C4 H gene controlled by SA and COS was different, COS treatment inhibited the expression of C4 H, SA promote C4 H gene expression. Compared with the CK, C4 H expression levels of COS treatment were lower than CK all the time, C4 H expression levels of SA treatment gradually increased.