Cured tobacco having a lower concentration of tobacco specific nitrosamines, can be produced from a transgenic tobacco plant having a heterologous nucleotide sequence encoding a polypeptide that catalyzes production of active oxygen species. The heterologous nucleotide sequence is operably coupled to a regulatory nucleotide sequence that directs expression of the polypeptide. The regulatory nucleotide sequence can include constitutive and/or inducible promoter elements.