Allelic variation of the Waxy gene in foxtail millet [Setaria italica (L.) P. Beauv.] by single nucleotide polymorphisms.
The Waxy (Wx) gene product controls the formation of a straight chain polymer of amylose in the starch pathway. Dominance/recessiveness of the Wx allele is associated with amylose content, leading to non-waxy/waxy phenotypes. For a total of 113 foxtail millet accessions, agronomic traits and the molecular differences of the Wx gene were surveyed to evaluate genetic diversities. Molecular types were associated with phenotypes determined by four specific primer sets (non-waxy, Type I; low amylose, Type VI; waxy, Type IV or V). Additionally, the insertion of transposable element in waxy was confirmed by ex1/TSI2R, TSI2F/ex2, ex2int2/TSI7R and TSI7F/ex4r. Seventeen single nucleotide polymorphims (SNPs) were observed from non-coding regions, while three SNPs from coding regions were non-synonymous. Interestingly, the phenotype of No. 88 was still non-waxy, although seven nucleotides (AATTGGT) insertion at 2,993 bp led to 78 amino acids shorter. The rapid decline of r (2) in the sequenced region (exon 1-intron 1-exon 2) suggested a low level of linkage disequilibrium and limited haplotype structure. K (s) values and estimation of evolutionary events indicate early divergence of S. italica among cereal crops. This study suggested the Wx gene was one of the targets in the selection process during domestication.
D000483:Alleles; D000595:Amino Acid Sequence; D000688:Amylose / Q000378:metabolism; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D017343:Genes, Plant; D014644:Genetic Variation; D006239:Haplotypes; D015810:Linkage Disequilibrium; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D032983:Setaria Plant / Q000235:genetics* / Q000378:metabolism; D013214:Starch Synthase / Q000235:genetics* / Q000378:metabolism
D017931:DNA Primers; D018744:DNA, Plant; D010940:Plant Proteins; C060756:waxy protein, plant; D000688:Amylose; D013214:Starch Synthase