Related Genes Discovery And Analysis Of Anthocyanin Biosynthesis After Debagging In 'Pingguo' Pear Fruit

The appearance and intrinsic quality of the fruit together form the overall quality of the fruit.High quality fruit can better increase the commercial value of the fruit.The color of fruit peel is one of the important indicators of the appearance quality.After the bag is processed,it will be quickly colored in a short time,and the background color becomes lighter and the coloring is more vivid.This study intends to screen the double-layer paper bags which are most suitable for ‘Pingguo' pear cultivation;then study the changes of pigment content in the growth and development of ‘Pingguo' pears,and select the color related differentially expressed genes from the transcriptome level,cloning and expression analysis of key transcription factors in anthocyanin biosynthesis and further explores the mechanism of coloration of bagged fruits,thereby establishing the molecular mechanism of red peel formation and provide theoretical basis for molecular genetic breeding of ‘Pingguo' pear.The main findings are as follows:1.After the double-layered bagging of ‘Pingguo' pear fruit,the fruit coloring index increased significantly,the fruit point became smaller,and the fruit density decreased.The content of soluble solids,total sugar and titratable acid decreased slightly compared with the control.There is no effect on the average fruit weight of ‘Pingguo' pears,and the effects on the different peeling hardness of fruits are different.Based on the comprehensive evaluation of the results of this experiment,it is considered that the treatment of the Lvda and Lvzhou double-layer bags is the most suitable bag for ‘Pingguo' pear bagging.2.After the bagging of ‘Pingguo' pear fruit,the total chlorophyll content of the peel was significantly decreased.The chlorophyll content of the ‘Pingguo' fruit bag fruit peel was significantly lower than that of the unbagged fruit.The chlorophyll content of the unpacked fruit increased gradually and then slowly decreased.After bagging,the synthesis of chlorophyll was significantly inhibited,and the chlorophyll content in the fruit continued to decrease.3.The maximum fluctuation of anthocyanins in bagging fruit during the whole development period is that after the bag is unpacked,it shows a sharp upward trend,indicating that after the bag is unpacked,the fruit is transferred from dark conditions to light conditions,and anthocyanin synthesis is accelerated.The background color of the fruit surface is light yellow,and the peel has a bright red color;the content of anthocyanin in the control fruit has experienced a sharp rise,and then the decline has a slight increase in the fruit ripening period.It can be seen that the anthocyanin synthesis in the whole period of fruit bagging has little change,and the anthocyanin has increased significantly after the bag is unpacked.Bagging inhibits anthocyanin synthesis.4.Using Illumina high-throughput sequencing platform to analyze three developmental stages after debagging of ‘Pingguo' pears,it was found that in the rapid accumulation stage of anthocyanins,there were 1371 differential gene expressions,of which 575 the differential expression was up-regulated and 796 were down-regulated.Thirty-two genes related to anthocyanin synthesis were identified,and 32 genes were screened by real-time PCR.The results were consistent with the transcriptome results.5.The overexpression vector of Pb Myb4-like1,Pb Myb4-like2,Pb MYB1R1 and Pb WDR transcription factor was constructed,the transient transformed fruit of tomato was obtained.There was no difference between the color of the transgenic fruit and the control,and p RI-Pb MYB1R1 was difference between the control and other treatments by measuring the anthocyanin content of tomato.