Christiane Förster

   Department of Biochemistry
   Volatile Biosynthesis
 Phone:+49 (0)3641 57 1320Max Planck Institute for Chemical Ecology
 Fax:+49 (0)3641 57 1302Hans-Knöll-Straße 8
  emailD-07745 Jena

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Benzoxazinoids (BXDs) are plant secondary metabolites that are well known for their defensive and allelopathic properties. They are mainly produced in plants of the grass family (Poaceae), including agricultural crops such as maize, wheat, and rye. The biosynthesis of BXDs has been extensively studied in maize and especially the biosynthetic pathway for the benzoxazinoid hydroxamic acids is fully elucidated in this plant. The core pathway starts from indole-3-glycerol phosphate, which undergoes several oxidations, a glucosylation, and a methylation leading to 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside (DIMBOA-Glc). DIMBOA-Glc is the most abundant BXD in undamaged maize, however, after herbivore feeding it is converted to a variety of other compounds such as HDMBOA-Glc, DIM2BOA-Glc , and HDM2BOA-Glc. In collaboration with the groups of Georg Jander (Boyce Thompson Institute, Ithaca, USA) and Matthias Erb (University of Bern, Switzerland), we have recently identified and characterized the enzymes involved in the formation of HDMBOA-Glc, DIM2BOA-Glc, and HDM2BOA-Glc in maize (see figure).
The aim of the present study is to identify respective enzyme homologues in wheat and to investigate how they might have evolved. Preliminary BLAST analysis with the wheat genome revealed no direct orthologues, suggesting a convergent evolution of DIMBOA-Glc metabolism in the grasses. Since fungus infestation can induce the conversion of DIMBOA-Glc into other BXDs in wheat, a transcriptomic dataset derived from non-infested and fungus-infested wheat plants will help us to identify upregulated candidate genes.
Further on, we are interested in elucidating the biosynthesis of benzoxazinoid lactams such as HMBOA-Glc in both maize and wheat. These compounds are frequently found in the leaves besides benzoxazinoid hydroxamid acids, but the enzymes responsible for their formation are still unknown and the biological roles of these compounds are unclear.
last updated on 2018-11-12