Metabolic profiling for benzoxazinoids in weed-suppressive and early vigour wheat genotypes

Replicated wheat (Triticum aestivum L.) cultivar trials were performed in commercial fields in moderate to low rainfall zones at Wagga Wagga (572 mm) and Condobolin (449 mm) NSW in 2014 and 2015. At each experimental site, crop and/or weed growth were monitored at selected growth stages including tillering, vegetative, grain filling, harvest and post-harvest to the crop. In addition, shoots, roots, rhizoplane and bulk rhizosphere soil samples were collected. All shoot and root samples were extracted in methanol using an automated Buchi high pressure extractor while soil samples were extracted using a rotary shaking method. Extracts were profiled for unique secondary plant products including benzoxazinoids (BXs) using liquid chromatography coupled to mass spectrometry. Metabolic profiling of wheat cultivar shoots, roots, and soils resulted in detection of up to 14 BXs including BX glycosides and other metabolites of interest. Both qualitative and quantitative differences in BXs were observed and were cultivar and location dependent. Plant part and rhizosphere location (distance from root) also impacted BX concentration. Additional metabolic profiling is now underway and will provide crucial information regarding crop metabolism and biosynthesis of metabolites associated with weed suppression in commercial wheat cultivars.