Analysis of Genetic Effect of Fruit Color Controlled by Epistatic Genes in Eggplant
[Objective]Fruit color is an important trait that affects the commercial value of eggplant fruit.By analyzing the causes for the special segregation ratio of individual plants with purple red peel and with white peel in the F2 population constructed by crossing between two white-fruit parents,this paper could lay the foundation for elucidating the mechanism of epistatic gene interaction on regulating eggplant fruit coloration.[Method]The white-flower and white-peel female parent 19141 with mutation at the structural gene ANS involving in the anthocyanin biosynthesis pathway,white-flower and white-peel male parent 19142 with unknown mutation genes involving in the anthocyanin biosynthesis pathway,and their F1 population with purple red peel and F2 population with separate peel colors were used to explore the epistatic inheritance of eggplant fruit coloration.Genes and their mutation patterns were studied by cloning the known genes,D(SmMYBl)and Y(SmDFR)related to peel color in male parent 19142.Molecular basis of peel color-controlling epigenetic genes was analyzed by developing molecular markers based on genetic variations of peel color genes,analyzing the relationship between genotype and phenotype in E4450F2 population,and crossing with other eggplant parents without anthocyanin pigmentation in peel.[Result]The segregation ratio of plants with purple red fruit and white fruit in E4450 F2 progeny was consistent with the segregation ratio of 27:37 controlled by three pairs of epistatic genes,that is,mutations occurred at the P gene locus in 19141,with genotype DDppYY,and mutations occurred at both D and Y gene loci in 19142,with genotype ddPPyy.The results of cloning and sequencing showed that alternative splicing occurred in SmMYB1 of 19142,which led to the second exon skipping.In 19142,SNP(C→G)in the promoter region's-326 bp upstream of the start codon resulted in the absence of a CAAT-box cis-acting element in SmDFR gene.An SNP,G to C,at the last base of the second exon,was annotated as splicing mutation,which might cause abnormal function of SmDFR gene in 19142,resulting in the eggplant peel's inability to synthesize anthocyanin.Based on the genetic variation of SmMYB1,SmANS and SmDFR,the functional molecular markers were developed,and the progenies of E4450F2 were genotyped.The results showed that genotype and phenotype were completely consistent.D_P_Y_corresponded to phenotypes of purple flower and purple red peel,ddP_Y_corresponded to phenotype of purple flower and white peel,DD_P_yy,D_ppyy,ddppY_,ddP_yy and ddppyy genotypes corresponded to white flower and white peel phenotypes.When 19142 was crossed with white-peel inbred line 19147(ddPPYY),and green-peel inbred line 19144(DDPPyy),it was found that the fruit color of the two F1 progenies were white and green,respectively,and there was no anthocyanin pigmentation in the peel,which further proved that 19142 was a double mutant in SmMYBl and SmDFR.[Conclusion]When two eggplant parents without anthocyanin pigmentation in the peel were crossed,the peel of the F1 generation had anthocyanidin pigmentation,and the segregation ratio of plants with anthocyanin pigmentation and non-anthocyanin pigmentation in F2 population was 27:37,it was because one of the parents had a mutation at a gene locus in the anthocyanin biosynthesis pathway,and the other parent had mutations at two other loci in the anthocyanin biosynthesis pathway.When two parents without anthocyanin pigmentation were crossed,the peel of F 1 was able to synthesize anthocyanin and present purple red color,which was due to the simultaneous dominance of three epistatic gene loci D,P and Y,and anthocyanin biosynthesis was restored.Mutation of the structural gene of SmANS or SmDFR inhibited anthocyanin biosynthesis in all parts of the plant.The regulation of transcription factor mutation SmMYBl was tissue specific,and its mutation inhibited anthocyanin biosynthesis in the peel,but did not inhabit anthocyanin biosynthesis in the flower.
eggplantpeel colorepistatic geneanthocyaningenetic law
国家科技期刊平台
NSTL
万方数据
维普
