Missing link in glucosinolate biosynthesis identified - 03.07.2009

A major breakthrough in the rapidly expanding field of synthetic biology will be published in Nature Chemical Biology vol. 5, issue 8, on 20. July 2009. A previously unknown enzyme was discovered and the authors demonstrate the ability to engineer the multi-step biosynthetic pathway of the cancer-preventive compound benzylglucosinolate into tobacco. 

 

Glucosinolates are sulfur-containing secondary metabolites giving cruciferous plants their characteristic flavor and increasing the positive effect of broccoli and related vegetables on human health. In plants the glucosinolates play an important role as natural insect and microbe deterrents. Accordingly, the ability to engineer these compounds into non-cruciferous plant is highly desirable for improved crop protection through increased insect and pathogen resistance. In the context of biomedicine and functional foods, development of novel glucosinolate-producing plants could play an important role in prevention of cancer.

 

 

The origin and the mechanism of incorporation of sulfur in glucosinolates were previously unknown. This study revealed glutathione as the sulfur donor in the biosynthesis of glucosinolates. In addition, the gene encoding the biosynthetic enzyme GGP1, γ -glutamyl peptidase 1, which catalyzes the transfer of the sulfur group, was identified. GGP1 is the first member of a new class of plant enzymes. Previously the transfer of sulfur was regarded as the missing link in the glucosinolate biosynthesis. This gap in knowledge has now been bridged, and transfer of the entire biosynthetic pathway has been made possible.

 

Engineering of the production of benzylglucosinolate in tobacco plants has generated a technological platform that extends beyond glucosinolates and is readily applicable for the engineering of other secondary metabolites and for gene discovery in general.

 

Link to advance online publication of Geu-Flores et al (2009) Glucosinolate engineering identifies a -glutamyl peptidase.

For further information, please contact Professor Barbara Ann Halkier, email or telephone 353 33342.