The Recessive Allele in the Soybean Maturity Locus E9 Causes Delayed Flowering

In soybean, the molecular basis of natural variation in time to flowering and maturity is poorly understood. Using a cross between early-maturing soybean cultivars, Chen Zhao from Hokkaido University led researchers to study the soybean flowering genes. They focused on E9 locus, one of two maturity loci in the progeny.

Analysis revealed that E9 is an ortholog of Arabidopsis FLOWERING LOCUS T, (FT2a). The recessive e9 allele was transcribed at a very low level compared with the dominant E9 allele, causing delay in flowering. The recessive e9 allele also had a Ty1/copia–like retrotransposon, SORE-1, inserted in its first intron. This insertion decreased FT2a expression through allele-specific transcriptional repression.

The soybean maturity gene E9's recessive allele delays flowering because of its low expression. E9's low expression is due to allele-specific transcriptional repression caused by the SORE-1, insertion in the recessive allele.

For more information, read the full article on BMC Plant Biology.