An Active CACTA-Family Transposable Element is Responsible for Flower Variegation in Wild Soybean Glycine soja

Abstract

A plant producing flowers with purple and white variegation was discovered in an accession of Siebold & Zucc. that was introduced from Russia. The mutant line was designated as B00146-m. Lines with white flowers (B00146-w) and purple flowers (B00146-r) were developed from the progeny of B00146-m. The flower color was controlled by the locus encoding a flavonoid 3′5′-hydroxylase (F3′5′H). The allele for variegated flowers was designated as . The gene symbol was approved by the Soybean Genetics Committee. Polymerase chain reaction (PCR) suggested that a DNA fragment with a molecular size of ∼3.9 kb was inserted in the first exon of the ′′ gene in B00146-m whereas such insertion was not observed in B00146-w and B00146-r. These results suggested that an active mobile element was inserted in the first exon and was responsible for flower variegation. The inserted fragment was identified as a 3883 bp long CACTA-family transposable element and it was designated as . Similarity of overall sequence and terminal inverted repeats suggested that and the soybean lectin gene transposable element make up a subgroup. Frequency of germinal reversion was low probably due to the integration into an exon. had a truncated version of the transposase gene and may be a nonautonomous element.