The Mechanism Of Strawberry FvMYB17 Regulates Anthocyanin Synthesis

As a fruit with high economic value,strawberry color is one of the important quality evaluation criteria,which is mainly affected by the anthocyanin accumulation level.In this study,FvMYB17 gene have been overexpressed in forest strawberry 'Ruegen'.We found that the leaves and stems of transgenic plants had significant anthocyanin accumulation.The results of point mutation technology,yeast one-hybrid,yeast two-hybrid and firefly fluorescence report test proved that FvMYB17 is a positive regulator of anthocyanin synthesis.Its function is different from that of homologous transcriptional repressors of the same subfamily.The main reason is a point mutation in the C-terminal inhibitory domain of an amino acid.The results of this study enriched the regulation mechanism of anthocyanin synthesis in strawberry fruits,and provided a theoretical basis for strawberry fruit color breeding.The main results of this test are as follows:1.After PCR on DNA level and RT-qPCR detection on RNA level,we obtained 6 FvMYB17-overexpressing strawberry lines.The leaves and stems of transgenic plants were significantly redder than the control.Fruits and anthers also had some pigment accumulation than the control.2.High performance liquid chromatography analysis showed that: HPLC detection of FvMYB17-overexpressing strawberry plants significantly increased Cy3 G,Pg3G,Q3-g,K3-g,ellagic acid and(+)-catechin content in leaves and red fruits.3.Detection by RT-qPCR method showed that the expression of anthocyanin synthesis-related genes PAP1,PAL1.1,PAL1.2,C4 HI,CHI,CHS,4CL2,4CL1.1,F3 H,ANS,DFR and UFGT in FvMYB17-overexpressing strawberry plants was significantly increased.4.Yeast two-hybrid experiments showed that FvMYB17 protein can interact with FvbHLH33 protein,and b HLH motif of FvMYB17 can be subjected to site-directed mutation.The site-directed mutation proteins FvMYB17M1 and FvMYB17M2 can still interact with FvbHLH33 protein.5.Yeast one-hybrid experiment and the firefly fluorescent reporter experiment showed that FvMYB17 transcription factor can bind to the F3 H gene promoter.After making changes to the FvMYB17 C2 inhibitory domain,the site-directed mutations of FvMYB17M3 and FvMYB17M4 have weakened the binding ability to the F3 H gene promoter,which indicates that FvMYB17 is regulating the expression of anthocyanin synthesis genes.