Study On Color Deterioration Related Genes Of Strawberry Based On Transcriptome Analysis

During postharvest storage,the color of strawberries will darken.The fruit discoloration will not only affect people’s sensory acceptability,but also seriously damage the quality of fruit storage.Previous studies of our laboratory found that high storage temperature(35℃)accelerated the discoloration of strawberry fruit.In order to explore the mechanism of high temperature treatment promoting the color deterioration of strawberry,the RNA-seq technique was used to sequence the high flux of strawberry fruit stored at 25℃ for 7 days and 35℃ for 7 days.Based on the analysis of two differentially expressed genes related to color under different temperature treatments,the differentially expressed genes were screened and its preliminary functional analysis was performed,and preliminary study on molecular mechanism of strawberry color deterioration under high temperature condition was discussed,so as to provide theoretical support for searching the method of controlling the color deterioration of postharvest fruits.The main results of this study are as follows:1 Color-related transcriptome analysis of strawberry under high temperature storage conditionBetween the strawberry fruits stored at 25℃ and 35℃ for 7 days,there were 19573 coexpression genes,1134 specific expression genes stored at 25 ℃ and 754 specific expression genes stored at 35 ℃.Hierarchical clustering analysis of differentially expressed genes showed that high temperature treatment significantly affected the expression of different genes in strawberry fruit.Differential expressed genes related to color deterioration analysis shows,there are 11 structural genes related to anthocyanin synthesis(PAL,CHS,LDOX,UAGT,etc.),9 transcription factors(MYB,bHLH and WKRY),and 7 transport genes associated with anthocyanin transport(MATE,GST).Meanwhile,15 phenolics metabolism enzyme genes(PPO,POD,Laccase,SOD,GRX,UF3GT)were analyzed.Among them,the structural genes in the anthocyanin synthesis pathway were up-regulated,which promoted the accumulation of anthocyanin under high temperature.It was concluded that the accumulation of anthocyanin was closely related to the color deterioration of strawberry under high temperature.qPCR was used to identifysignificant differential genes related to fruit color deterioration,and the results were consistent with the transcriptome data.2 The separation of UF3GT3 and its bioinformatics analysisThe CDS length and DNA length of the UF3GT3 gene were 1437 bp,that is,there is no intron spacer sequence in the coding region of the gene.The homologous gene homology found that UF3GT3 has a high homology with the FaGT3 gene in strawberry.It is presumed that it may act on flavonoids and play a certain role in fruit ripening and senescence..The protein characteristics of UF3GT3 show that the protein codes 478 amino acids with a molecular weight of about 52.86 kD.There are a large number of alpha helix and random curl in its structure,and the water solubility is general and the protein stability is poor.At the same time,the gene sequence also contains 5 conserved domains.The analysis of the promoter sequence of UF3GT3 shows that the region contains more core promoter components TATA-box,enhancer element CAAT-box,and some light response elements and low-temperature response elements.3 Preliminary function analysis of UF3GT3 gene by overexpression and silencing technologyThe pRI-OeUF3GT3 overexpression vector and pK7-UF3GT3 i interference vector of UF3GT3 were successfully constructed by pRI101-An-EGFP and pK7GWIWG2D(II)respectively.After the instant transformation of the postharvest strawberry in the period of the big green fruit,the bright green fluorescence was observed in the full red fruit,but not in the control fruit,indicating that the transient transfection of Agrobacterium tumefaciens was successful.Verification by qPCR,the expression of UF3GT3 in the strawberry fruit of gene interference and overexpression was 52% and 4.32 times,separately,indicating that the gene overexpression and interference were successful.UF3GT3 gene overexpression and silencing of strawberry fruit increased and reduced total flavonoids and total phenol content higher than 15%,and anthocyanin was less than5%,indicating that the increase of the expression of UF3GT3 gene can promote the accumulation of flavonoids and other phenols,indicating that the UF3GT3 gene has a positive modulation on the synthesis metabolism of phenolic substances in strawberry fruit.