Two point mutations identified in emmer wheat generate null Wx-A1 alleles.
In this report, the Wx-A1 mutations carried by a Triticum dicoccoides line from Israel and a Triticum dicoccum line from Yugoslavia are characterized. A single nucleotide insertion in the T. dicoccoides null allele and a single nucleotide deletion in the T. dicoccum null allele each cause frameshift mutations that induce premature termination codons more than 55 nucleotides upstream of the last exon-exon junction. In both mutants, Wx-A1 transcripts were detectable in 10 day post-anthesis endosperm by relative RT-PCR. However, transcript levels of the T. dicoccoides and T. dicoccum null alleles were reduced to approximately 6.5 and 1.5% of wild-type, respectively. Therefore, the lack of Wx-A1 protein in the mutants appears to be largely due to nonsense-mediated mRNA decay. The two mutations described here arose independently, and are not related to either of the Wx-A1 mutations identified in common wheat.
Saito
M
M
Department of Crop Breeding, Tohoku National Agriculture Research Center, 4 Akahira, Shimo-Kuriyagawa, Morioka, 020-0198, Iwate, Japan.
Nakamura
T
T
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D018389:Codon, Nonsense; D018744:DNA, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism*; D018749:RNA, Plant; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013214:Starch Synthase / Q000235:genetics*; D014908:Triticum / Q000235:genetics*
D018389:Codon, Nonsense; D018744:DNA, Plant; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C060756:waxy protein, plant; D013214:Starch Synthase