Isolation Of MYB Transcription Factor Genes And Expression Analysis Of Anthocyanin Bionsynthesis Genes In Red-flowered Strawberry

The flowers of all Fragaria are white,the red-flowered strawberry,known as an ornamental strawberry is an intergeneric hybrid,which derived from the cross of cultivated pineapple strawberry(Fragaria × ananassa Duch.)and a purple-colored marsh cinquefoil relative(Potentilla palustis(L.)Scop.),and constantly backcross with cultivated.It is increasingly valued due to its excellent ornamental traits,but the accumulation of its color was formation rarely reported.MYB transcription factor family is one of the largest members of transcription factors in plant,by regulating the expression pattern of structure genes at the transcription level,extensively involved in growth and metabolic processes.In this study,the hybrid seedlings with different flower colors from the crosses of Pink Princess × Pretty Beauty and Pretty Beauty × Pink Princess were used as materials to conduct qualitative and quantitative analysis of pigments using HPLC-MS method.Basing on the results of petals transcriptome sequencing cloned two MYB transcription factor gene,the bioinformatics and expression patterns were analyzed,a preliminary analysis of MYB transcription factors in red strawberry and the metabolic regulation of anthocyanin synthesis.The results were as follows:1.The content of anthocyanins and the content of flavonoids and flavonoids in red-flowered strawberry petals with different color and different bud development stages were analyzed.The results showed that the accumulation of anthocyanin was not detected in petals of white and uncolored buds.In addition to the detection of a large amount of cyanidin 3-O-glucoside(Cy3G)in red,deep flour,pink and light pink petals,pelargonidin 3-O-glucoside(Pg3G),delphinidin 3-0-(feruloyl)-glucoside(Dp3feG)and other seven kinds of pigment,and the different colors during development are mainly caused by the content of Cy3G.2.According to the sequencing results petal transcripts,two MYB unigene sequences were screened by RPKM method and homologous alignment.Significantly.specific primers were designed,the RT-PCR method was used to isolate the complete CDS sequences of two MYB transcription factor genes,named PfaMYBl and PfaMYB86,respectively.Bioinformatics analysis showed that the two sequences had two typical MYB domains at the N-terminus and had a high similarity to the reported MYB transcription factor domains.It was presumed that both PfaMYBl and PfaMYB86 were R2R3-MYB Transcription factor.3.Real-time quantitative PCR results showed that PfaMYBl was expressed in petals,as well as fruits.roots,stems and leaves,also in different colored and different developmental petals and different buds,and specific expression in flowers and fruits.The expression level of PfaMYB86 in different flower color,different tissues and different developmental was not significantly correlated with the coloration.4.The results showed that CHS,CHI,ANS and DFR genes were significantly correlated with anthocyanin content in petals at different developmental stages,which might be related to the effect of Cy3G on red-flowered strawberry.The expression of F3'5'H gene was relatively high during early stage,but the petals did not accumulate a large amount of delphinidin,suggesting that the substrate of ANS,DFR and UFGT1 genes specificity leads to low synthesis of delphinidin or delphinidin of aglycones.