2022 Volume 91 Issue 2 Pages 229-239
This study investigated genetic polymorphism related to anthocyanin composition variation in lisianthus (Eustoma grandiflorum) flower petals. Three different bands were detected by genomic polymerase chain reaction using specific primers based on the reported flavonoid 3',5'-hydroxylase (F3'5'H) gene sequence. Our genetic study revealed that they were allelic. They were named F3'5'H1-1, F3'5'H1-2, and f3'5'h1-2. F3'5'H1-1 and F3'5'H1-2 differed in the length of the intron. Allele f3'5'h1-2 possessed a retrotransposon insertion in the first exon, but otherwise, its gene sequence was almost identical to that of F3'5'H1-2. This retrotransposon is a Ty1-copia type retrotransposon and was designated as the retrotransposon of Eustoma grandiflorum 1 (rTeg1). The mauve flower line ‘ME’ and red-purple flower line ‘PRP’ were homozygous for F3'5'H1-1 and mostly accumulated cyanidin, with a small amount of delphinidin, in flower petals (the Cy major phenotype). The violet flower line ‘RV’ was homozygous for F3'5'H1-2 and accumulated only delphinidin (the Dp major phenotype). The pink-red flower line ‘AK’ was homozygous for f3'5'h1-2, accumulated pelargonidin, and lacked delphinidin (the Pg major-non Dp phenotype). Segregation analysis of the F2 population from ‘ME’ × ‘RV’ revealed that F3'5'H1-2 was associated with the Dp major phenotype, and the delphinidin major trait was dominant in the Cy major phenotype. All the Cy major phenotype plants in the F2 population possessed homozygous F3'5'H1-1. Genetic analysis of the F2 population from the cross between delphinidin-containing and delphinidin-lacking strains revealed that the homozygous f3'5'h1-2 genotype co-segregated with the Pg major-non Dp phenotype, which was recessive to the delphinidin-containing phenotypes. Expression analysis of the F3'5'H gene demonstrated that an abnormal mRNA was transcribed from the F3'5'H gene in the homozygous f3'5'h1-2 line by the insertion of rTeg1. Therefore, these F3'5'H gene polymorphisms can be used as DNA markers for breeding lisianthus based on flower color.
