| The newly germinating leaves of red-leaf peach are brilliant red in spring,but they would turn green under the high tempreture condition in summer,the leaf color gradually from red to green and lose ornamental value,not only shorten the ornamental period,ornamental value is greatly reduced,a negative impact on the production and application of red leaf peach.In contrast,some early maturing peach varieties have dark green leaves before fruit harvest,and anthocyanin accumulation starts in the leaf petiole.the color can make up for lack of red-leaf peach "green period",has a great development prospect in Landscape Application in breeding,but also enrich the theory ofcolor leafed plants coloration mechanism.This research selected two red leaf color peach cultivars(’tsuku-ba-5’、’Rutgers redleaf’)and two early maturing peach cultivars(’Zaomei’,’Chunlei’)as the trail materials,green leaf peach cultivar ’Jingmi’ as CK.We analyzed and compared their anthocyani contents,color changes and the expression of the structural genes and the regulatory gene involved in the anthocyanin biosynthetic pathway in their leaves.The leaves were sampled during their growth season.the structural genes included CHS、CHI、F3H、F3’H、DFR、LDOX、UFGT and the regulatory gene included MYB10、bHLH3、WD40、MYBPA1、MYB15、MYB16、MYB111、MYB123.This research studied physiological mechanism of leaf color change of peach with different coloration type cultivars,and the impact on the coloration of the expression levels of the related genes.The main results of the study are as follows:1.In order to study the function of the transcription factor MYB10 in the coloration of peach red leaves,the full-length cDNA sequence of MYB10 in red-leaf peach cultivar’Zhubo-5,(Prunus persica f.alropurpurea)was successfully cloned by PCR.The gene was submitted to Genbank with the assigened accession number of GI:KP315904.Bioinformatics analysis showed that MYB10 had a complete opening reading frame(ORF)containing 678bp,which encode 225 amino acids.The predicted protein molecular weight is 26.56 kDa and the theoretical pI is 8.97.The secondary structure prediction of MYB10 protein showed that about 34.22%of amino acids formed into alpha helix,15.11%in extended strand,10.67%in beta turn and 40%in random coil.It does not have classical signal peptide and transmembrane domain.The subcellular analysis indicated that the protein might function in the cytoplasmic.Polygenetic analysis showed that MYB10 protein in red-leaf peach shares closer evolutionary relationship with that in Prunus persica,the homology is as high as 97%.According to the amino acids sequence analysis,the protein contains one potential serine phosphatase site and two threonine sites.Real-time qRT-PCR analysis showed that the expression of MYB10 gene was positively correlated with the anthocyanin content in red-leaf peach leaves,which indicates that MYB10 might play important role in the biosynthesis of anthocyanin.2.Red leaf peach two varieties of anthocyanin content decreased in summer,"green"phenomenon,the fall and rise;early maturing peach two varieties of summer fruit,leavesturning red,anthocyanin content has been increased;green peach leaf is green,the content of anthocyanin remain basically unchanged.Relative anthocyanin content changes of L*,a*,b*color value and 5 kinds of peach cultivars.Roles in the regulation of gene expression(MYB10,WD40,MYBPA1,MYB16,MYB111)and the structural gene(CHS,CHI,F3’H,DFR,LDOX,UFGT)and expression of anthocyanin content in leaves was positively related to thelevel of regulation,some effects on anthocyanin biosynthesis in peach leaves accumulated;gene MYB15 and the expression of MYB123 and the leaf anthocyanin content showed a negative correlation;the expression of F3H and bHLH3 in the 5 Peach Cultivars in the three seasons are higher.This research has very important theoretical guiding significance for the future of color leafed plant genes related to anthocyanin metabolic pathway in transgenic andcontrol plants by leaf color. |
