A histidine decarboxylase-like mRNA is involved in tomato fruit ripening.

DNA sequencing of a tomato ripening-related cDNA, TOM 92, revealed an open reading frame with homology to several pyridoxal 5'-phosphate histidine decarboxylases, containing the conserved amino acid residues known to bind pyridoxal phosphate and alpha-fluoromethylhistidine, an inhibitor of enzyme activity. TOM 92 mRNA accumulated during early fruit ripening and then declined. Fruit of the ripening-impaired tomato mutant, ripening inhibitor (rin), did not accumulate TOM 92 mRNA, and its accumulation was not restored by treatment of fruit with ethylene. The TOM 92 mRNA was not detected in tomato leaves and unripe fruit.