Genetics of proteome variation for QTL characterization: application to drought-stress responses in maize

The proteome is emerging as an important concept of the post-genome era. Po werful nucleic acid approaches (EST, DNA chips, etc.) are still limited bec ause DNA sequences and mRNA levels are not sufficient to predict the struct ure, function, amount, and activity of the proteins in the cell, The proteo me can now be subjected tb large-scale analysis, owing to spectacular progr ess in the techniques of identification of proteins excised from two-dimens ional (2-D) gels. in addition, computer-based analysis of 2-D gels makes it possible to quantify the protein spot intensities, which are commonly gene tically variable. The loci controlling these variations may be mapped on th e genome (PQLs, Protein Quantity Loci), Beyond the interest for regulatory genetics and molecular biology, the PQL methodology can provide an addition al tool for the difficult task of identifying QTLs (Quantitative Trait Loci ), in the context of the candidate gene approach. The PQL methodology is pr esented with the example of the phosphoglycerate mutase Variations in maize , and the candidate gene/protein approach is illustrated for traits respons ive to drought stress.