1. POSSIBLE USE OF A BIOTECHNOLOGICAL
APPROACH TO OPTIMIZE AND REGULATE
THE CONTENT AND DISTRIBUTION OF
CYANOGENIC GLUCOSIDES IN SORGHUM TO
INCREASE FOOD SAFETY
Bowater/MiraImagesdailykos

2. Why CyanogenicGlucosides
as a Topic?
• Cyanogenic Plants?
• CyanogenicGlucosides belong to the class of
phytoanticipins
• Mechanical disruption of plant tissue?

3. • What are CyanogenicGlucosides?
• There are four type of linkages present
between glycone and aglycone:
1. C-linkage/glycosidic bond, "nonhydrolysable
by acids or enzymes"
2. O-linkage/glycosidic bond
3. N-linkage/glycosidic bond
4. S-linkage/glycosidic bond
• Toxicity of CyanogenicGlucosides
1. Repel Herbivores
2. Relationship between microorg
3. Easy hosts for fungi and insects-easy
inceptors of pathogens
awakeandliving
Yikrazuul et al. 2008

4. Focus on Sorghum
(Sorghum bicolor L.)?
• Naturally occuringacyanogenic individuals found
in cyanogenic plant species- white clover
• Problem with Sorghum:

5. • Sorghum cyanogenicglucoside = dhurrin
• Problem with dhurrin? ---
hydrolysed by B-glucidosases
• Sorghum as animal fodder-sorghum forage
• Overall:

6. Plant Biotechnology --- please help!
Peter Stuart et al. 2012
Robyn O'Brien et al. 2012
There is a great need for acyogenic forage production

7. • Understand the regulation of dhurrin content in sorghum
seedlings. dhurrin synthesis in sorghum seedlings is regulated by
the rate of de novo synthesis of the biosynthetic enzymes.
• Dhurrin synthesis: involves two cytochrome P450s (CYP79A1 and
CYP71E1) and one UDP-glucosyltransfer- ase (UGT85B1)

8. Peter Kamp Busk et al. 2002

9. Kristensen et al., 2005; Jenrich et al., 2007

10. Kristensen et al., 2005; Jenrich et al., 2007

11. Kristensen et al., 2005; Jenrich et al., 2007

12. • Peter Kamp Busk2 and Birger Lindberg
Møller* Studies on Cyanide Potential
• the activity of the first enzyme in the pathway
is always rate limiting
• Outlook: CYP79A1 mutations
• TILLING for forage sorghum:
Cecilia K. Blomstedt et al. 2011

13. • P414L mutation in CYP79A1
Cecilia K. Blomstedt et al. 2011

14. How did we get to the P414L mutation?
Cecilia K. Blomstedt et al. 2011

15. Cecilia K. Blomstedt et al. 2011

16. Brandenburg et al. 200

17. • Cytochrome P450’s highly substrate specific
• P414L mutation decreases substrate affinity
• Normal: E-R-R triad: arginine (R) in PERF motif and arginine
residues (R) and glutamic acid (E) in KETLR motif
• locks the haem pocket of active site into proper position
• P141L mutation
Prosser et. al. 2006

18. References
• Blomstedt, C. K., Gleadow, R. M., O'Donnell, N., Naur, P., Jensen, K., Laursen, T., & Olsen, C. E.
(2012). A combined biochemical screen and TILLING approach identifies mutations in Sorghum
bicolor L. Moench resulting in acyanogenic forage production. Plant Biotechnology Journal, 10, 54-
66.
• Busk, P. K., &Moller, B. L. (2002, July). Dhurrin Synthesis in Sorghum Is Regulated at the
Transcriptional Level and Induced by Nitrogen Fertilization in Older Plants. Plant Physiology, 129,
1222-1231.
• Ganjewala, D., Kumar, S., S, A. D., &Ambika, K. (2010). Advances in cyanogenic glycosides
biosynthesis and analyses in plants: A review. ActaBiologicaSzegediensis, 54(1), 1-14.
• Halkier, B. A., &Moller, B. L. (1990, June 18). The biosynthesis of cyanogenicglucosides in higher
plants. The journal of biological chemistry, 54(1), 21114-21121.
• Prosser, D. E., YuDing, G., Zongchao, J., & Glenville, J. (2006, May). Structural motif-based homolgy
modeling of CYP27A1 and site-directed mutational analyses affecting vitamin D hydroxylation.
Biophysical Journal, 90(10), 3389-3409.
• Trigiano, R. N., Windham, M. T., & Windham, A. S. (2003). Plant pathology concepts and laboratory
exercizes. CRC Press, 447.
• Wheeler, J. L., &Mulcahy, C. (1989, December). Consequences for animal production of
cyanogenesis in sorghum forage and hay. Tropical Grasslands, 23(4), 21114-21121.