Structural features of the wheat plastome were clarified by comparison of the complete sequence of wheat chloroplast DNA with those of rice and maize chloroplast genomes. The wheat plastome consists of a 134,545-bp circular molecule with 20,703-bp inverted repeats and the same gene content as the rice and maize plastomes. However, some structural divergence was found even in the coding regions of genes. These alterations are due to illegitimate recombination between two short direct repeats and/or replication slippage. Overall comparison of chloroplast DNAs among the three cereals indicated the presence of some hot-spot regions for length mutations. Whereas the region with clustered tRNA genes and that downstream of rbcL showed divergence in a species-specific manner, the deletion patterns of ORFs in the inverted-repeat regions and the borders between the inverted repeats and the small single-copy region support the notion that wheat and rice are related more closely to each other than to maize.

No abstract

Polymerase chain reaction (PCR) with degenerate primers was utilized for partial cloning of the MADS box gene family from wheat (Triticum aestivum L.). PCR products corresponding to a part of the MADS box region were cloned and sequenced. Eleven individual clones sequenced were classified into seven types on the basis of the nucleotide sequence and five types on the deduced amino acid sequence, which included two wheat-specific MADS box protein sequences. RT-PCR analysis with degenerate primers revealed preferential expression of the MADS box genes in young spikes. Furthermore, genomic Southern blot analysis with degenerate PCR products as probes indicated that wheat MADS box genes constitute a multigene family and are dispersed throughout the genome.

No abstract