Submitted to: Genome
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/28/2004
Publication Date: 2/18/2005
Citation: Xu, M., Palmer, R.G. 2005. Genetic analysis and molecular mapping of a pale flower allele at the w4 locus in soybean [glycine max (l.) merr.]. Genome. 48:334-340. Interpretive Summary: Mutations, changes in the genetic constitution of plants, are responsible for variation. Most mutations are deleterious, but some result in modifications that contribute to plant improvement. Mutations that result from 'jumping genes' have created different flower color patterns in soybean. Our objective was to characterize genetically a pale flower mutant and to locate this mutant on a chromosome (the genetic factors that are transmitted from father and mother to progeny). The pale flower mutant is a member of the W4 family of genes that control flower color in soybean. The pale flower mutant is located on the chromosome that is called linkage group D2. The location of the pale flower mutant is at the end of linkage group D2, which makes it important for molecular geneticists because it extends the physical length of linkage group D2. The pale flower could be used as a distinguishing trait in soybean cultivars to identify the cultivar.
Technical Abstract: The w4-mutable line in soybean was identified in 1983, and was proposed to contain an autonomous transposon at the W4 locus, a major locus controlling the biosynthesis of anthocyanin in soybean. A new intermediate revertant that produces pale flowers was identified from the w4-mutable line. Through genetic analysis, we established that the pale flower mutation was conditioned by a new allele at the W4 locus, w4-p. The w4-p allele is dominant to the w4 allele but recessive to the W4 allele; and the w1 allele has an epistatic effect on the w4-p allele. Genetic Type Collection number T369 was designated for the 'pale' mutant (w4-pw4-p). A mapping population with 114 F2 individuals derived from a single F1 plant of the cross of Minsoy (W4W4) x Pale (w4-pw4-p) was used to map the W4/w4-p locus by using simple sequence repeat (SSR) markers. Results showed that the W4 locus was located at one end of molecular linkage group D2 between SSR marker Satt386 and the nearby telomere with the distance between W4 and Satt386 as 2.3 cM. The results of genetic analysis and molecular mapping analysis of the pale flower mutation are consistent with the hypothesis that the w4-m allele harbors an autonomous transposable element.