Dhurrin synthesis in sorghum is regulated at the transcriptional level and induced by nitrogen fertilization in older plants

Plant Physiol. 2002 Jul;129(3):1222-31. doi: 10.1104/pp.000687.


The content of the cyanogenic glucoside dhurrin in sorghum (Sorghum bicolor L. Moench) varies depending on plant age and growth conditions. The cyanide potential is highest shortly after onset of germination. At this stage, nitrogen application has no effect on dhurrin content, whereas in older plants, nitrogen application induces an increase. At all stages, the content of dhurrin correlates well with the activity of the two biosynthetic enzymes, CYP79A1 and CYP71E1, and with the protein and mRNA level for the two enzymes. During development, the activity of CYP79A1 is lower than the activity of CYP71E1, suggesting that CYP79A1 catalyzes the rate-limiting step in dhurrin synthesis as has previously been shown using etiolated seedlings. The site of dhurrin synthesis shifts from leaves to stem during plant development. In combination, the results demonstrate that dhurrin content in sorghum is largely determined by transcriptional regulation of the biosynthetic enzymes CYP79A1 and CYP71E1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cyanides / metabolism
  • Cytochrome P-450 Enzyme System / genetics
  • Cytochrome P-450 Enzyme System / metabolism
  • Fertilizers
  • Gene Expression Regulation, Enzymologic / drug effects
  • Gene Expression Regulation, Plant / drug effects
  • Glycosides / metabolism
  • Mixed Function Oxygenases / genetics
  • Mixed Function Oxygenases / metabolism
  • Nitrates / pharmacology
  • Nitriles / metabolism*
  • Nitrogen / pharmacology*
  • Plant Leaves / genetics
  • Plant Leaves / metabolism
  • Plant Stems / genetics
  • Plant Stems / metabolism
  • Poaceae / genetics
  • Poaceae / metabolism*
  • Potassium Chloride / pharmacology
  • Potassium Compounds / pharmacology
  • RNA, Messenger / drug effects
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Time Factors
  • Transcription, Genetic / drug effects


  • Cyanides
  • Fertilizers
  • Glycosides
  • Nitrates
  • Nitriles
  • Potassium Compounds
  • RNA, Messenger
  • cyanogenic glycosides
  • Potassium Chloride
  • Cytochrome P-450 Enzyme System
  • Mixed Function Oxygenases
  • cytochrome P450TYR
  • cytochrome P-450 CYP71E1 (sorghum)
  • Nitrogen
  • dhurrin
  • potassium nitrate