Based On Olive Fruit Transcriptome And Analysis Of Differentially Expressed Genes Related To The Metabolism Of Polyphenols

Chinese Olive is a subtropical fruit in southern China which has important economic value and the pharmacological action. However, huge differences in polyphenol content and flavor between different varieties and lack of genome and transcriptome of genetic information have seriously hindered the high-quality Olive varieties breeding and fruit quality characteristics, such as polyphenols metabolic regulation. In this study, the ordinary varieties’Changying’and its bud mutation varieties’Qinglan’as experimental materials, using the Illumina high-throughput transcriptome sequencing (RNA-seq) technology to screen the genes differentially expressed between the two varieties of polyphenol metabolism process for the first time. The main results are as follows:1.Determination of’Changying’and’Qinglan’fruit at different developmental stages of the contents of polyphenols and flavonoids by UV spectrophotometry. Results show that’Changying’and’Qinglan’fruit polyphenol content increased gradually with the growth since 40DAF and reached the peak in 130DAF, and then began to decrease; Changying’s flavonoids content changes in the same way, but Qinglan’s flavonoids content decreased slightly in 70d-100d, but overall content is still an upward trend, they all reached the peak in 130d, and then began to decline.It is worth noting that Changying’s polyphenols and flavonoids content is about 2 times of the Qinglan.2. Chinese Olive fruits are rich in phenols, polysaccharide, protein, and some other secondary metabolites. According to these marked characteristics, this experiment used the BioTeke total RNA Extraction Kit Method, Trizol Method and CTAB Method to extract total RNA of Olive fruits. At the same time, the ultraviolet spectrophotometer was used to measure the OD value, and the Agarose Gel Electrophoresis was used to test their integrity. The results showed that the extracted RNA with high purity, the DNA and protein without pollution, the integrity is better, the results were less affected by the polysaccharide polyphenols. The extracted RNA accords with the requirement of the follow-up experiments.3.RNA-seq was used to sequence the Changying fruit in 40d (CY), Qinglan fruit in 40d(QY), Changying fruit in 130d(CS) and Qinglan fruit in 130d(QS). The results showed that the four cDNA library by assembling received a total of 67698 unigenes, average length of unigenes were about 750bp, and N50 is 1242bp, which has 39098 unigenes were successfully annotated to NR, Swiss-prot, KOG and KEGG database. 11751 significant differentially expressed genes (DEGs) were screened in the fruit of 130d, the expression of most genes in ’Changying’ were up-regulated compared to the ’Qing Lan’(9334,79.4%). In addition, a number of unigenes related to the metabolism of polyphenols were identified, including PAL, C4H,4CL, CHI, FLS and HPPD and other key genes, and HPPD may be the most important genes that cause changes in the content of polyphenols. Using qPCR to validate the expression level of candidate genes:C4H,4CL, COMT, AOC, POD, CAD, CHI, FLS, F5H, HCT and bglB. The results showed that the expression trends are basically consistent with the RNA-seq results, thus RNA-seq results are credible.