Figure 4.

Identification of CAD1 by draft genome sequencing, de novo assembly, and subsequent BLAST analysis. A, The gene structure of CAD1 in cv Sekizaisou (Sekizai-CAD1), cv Nezumigaeshi, and M. notabilis (MnCAD1). The genes include five exons (black boxes) and four introns (black lines). Nucleotide sequences of first exons (top line) and the deduced amino acid sequences (bottom line) of the genes are shown. After the first codon (ATG) in the first exon, a guanine hexad (blue) was detected in the sequence of Sekizai-CAD1, whereas both CAD1 alleles in cv Nezumigaeshi contain a guanine pentad. Amino acid sequences deduced from the first 29 codons of CAD1 in cv Nezumigaeshi and M. notabilis were identical, except for the residues encoded by the third codon. The guanine insertion into the first, second, or third codon of the first exon in Sekizai-CAD1 causes a frameshift mutation and subsequent premature stop codon. B, The phylogenetic tree of CAD sequences in different plant species. The amino acid sequence encoded by Sekizai-CAD1 was identical to those (319 amino acids) encoded by both entire CAD1 alleles in cv Nezumigaeshi if the inserted guanine residue was removed from the Sekizai-CAD1 sequence. The phylogenetic tree was constructed by using the entire CAD1 sequence of cv Nezumigaeshi as the CAD1 sequence of all M. alba cultivars.