Two point mutations identified in emmer wheat generate nullWx-A1alleles.

ISRAEL; YUGOSLAVIA

In this report, theWx-A1mutations carried by aTriticum dicoccoidesline from Israel and aTriticum dicoccumline from Yugoslavia are characterized. A single nucleotide insertion in theT. dicoccoidesnull allele and a single nucleotide deletion in theT. dicoccumnull 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-A1transcripts were detectable in 10 day post-anthesis endosperm by relative RT-PCR. However, transcript levels of theT. dicoccoidesandT. dicoccumnull 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 theWx-A1mutations identified in common wheat. [ABSTRACT FROM AUTHOR]