De novo synthesis of cyanogenic glucosides in insects

Danish title: De novo biosyntese af cyanogene glucosider i insekter

 

A number of Zygaena moths have been shown to be able to de novo synthesize and degrade the two cyanogenic glucosides linamarin and lotaustralin using intermediates similar to those identified in plants. Accordingly, the anabolic and catabolic enzyme systems involved in these processes may have similar characteristics as those from plants. Z. trifolii, Z. transalpina and Z. filipendula are able to use the model plant Lotus japonicus as their host plant. L. japonicus contains the same cyanogenic glucosides as the insects. The aim of this project is to isolate and characterize the enzymes involved in cyanogenic glucoside synthesis and degradation in Zygaena moths, and compare these to plant enzymes to find evidence of either horizontal gene transfer from plant to insect or convergent evolution of the enzymes. Gene expression analyses with focus on genes encoding enzymes related to cyanogenesis in these insects will be examined. Simultaneous analyses of the gene expression patterns in plants being attacked by insects will be examined to understand how the defence mechanisms in the plant and insect are competing to optimise survival of each organism. The effect of the ratio between linamarin and lotaustralin in the host-plant on their respective biosynthesis in Zygaena species will also be examined. Several different insect species (aphids, diamond back moth, Pieris, Mamestra, Spodoptera, Phaedon and possibly other species) that have been feeding on Arabidopsis thaliana leaves from either acyanogenic wild type or transgenic plants, containing the cyanogenic glucoside dhurrin, will be included in the studies. It will be determined whether these insects metabolize or sequester the cyanogenic glucosides and whether the presence of cyanogenic glucosides initiates detoxification systems in the insects.

 

Researchers involved: Mika Zagrobelny, Søren Bak, Birger Lindberg Møller

 

Foreign collaborators:

 

Financial support: Research Council for Technology and Production, Danish national Research Foundation, KVL PhD-stipend