Metabogenome: Discovering compounds a genes!

Source: Keurentjes, J.J.B., Fu, J., Ric de Vos, C.H., Lommen, A., Hall, R.D., Bino, R.J., van der Plas, L.H.W., Jansen, R.C., Vreugdenhil, D., and Koornneef, M. The genetics of plant metabolism. 2006. Nature Genetics, 38(7): 842-9

The authors used LC-QTOF MS to create metabolite profiles for two parental strains of Arabidopsis thaliana and 160 RIL descendants. They then genotyped these strains and ran QTL analysis on the >2000 metabolites they measured to come up with a staggering number of potential QTLs. Interestingly, a large number of compounds were not detected in either parent strain but only in the RILs. QTL hotspots were found and a study on a specific hotspot and its linked metabolites’ pathway carried out. This analysis was able to find the relative position in the pathway between two loci. Additionally, an analysis on a hotspot with unknown metabolites gave a set of metabolites to classify. Once discovered, the distinction in phenotypes revealed the presence of a previously unrealized enzyme in one of the parents. The authors close by stating that pathway elucidation and identification are possible through this high-throughput analysis, as well as metabolite grouping for identification.

Other notes:
-75% of compounds were assigned a QTL
-853 of 2129 metabolites not detected in either parent
-QTL for 1592 metabolites, roughly 2 QTLs per compound
-all AOP-related metabolites also map to MAM, while few MAM-metabolites map to AOP suggests AOP is downstream of MAM
-correlation between masses were calculated based on QTL profiles: vectors of P-values associated with markers
-co-occurrence of well-known or unknown metabolites may reveal pathway information