Insertion of a transposable element in Less Shattering1 (SvLes1) gene is not always involved in foxtail millet (Setaria italica) domestication

Recently, the less Shattering1 gene (SvLes1), an MYB transcription factor on chromosome V, in Setaria viridis, was reported to control the degree of seed shattering within S. viridis. SvLes1-1 and SvLes1-2 are the wild type (high shattering) allele and the reduced shattering allele, respectively. In addition to these two alleles, the loss-of-function allele through a transposable-element (TE) insertion in exon 2 was found in foxtail millet, a domesticated type of S. viridis, and was designated as SiLes1-TE. This gene is considered to be a domestication gene in foxtail millet. We screened 131 accessions of foxtail millet and found that 16 landraces (12.2%) of foxtail millet do not have the TE, despite expression of the non-shattering phenotype. We sequenced the SvLes1 gene of these 16 accessions and classified them into three alleles, SvLes1-1, SvLes1-2, and a new allele, SvLes1-3. The geographical distribution of these three alleles was different, suggesting that foxtail millet domestication and differentiation are more complex than expected.

Automated summary

The Less Shattering1 gene in foxtail millet controls the degree of seed shattering and includes wild type (SvLes1-1), reduced shattering (SvLes1-2), and a new allele with loss-of-function due to TE insertion (SiLes1-TE). A new allele, SvLes1-3, was discovered in 16 landraces of foxtail millet without the TE. This indicates that the domestication and differentiation of foxtail millet are more complex than expected.