Detection of Plant Low-Abundance Proteins by Means of Combinatorial Peptide Ligand Library Methods

The detection and identification of low-abundance proteins from plant tissues is still a major challenge. Among the reasons are the low protein content, the presence of few very high-abundance proteins, and the presence of massive amounts of other biochemical compounds. In the last decade numerous technologies have been devised to resolve the situation, in particular with methods based on solid-phase combinatorial peptide ligand libraries. This methodology, allowing for an enhancement of low-abundance proteins, has been extensively applied with the advantage of deciphering the proteome composition of various plant organs. This general methodology is here described extensively along with a number of possible variations. Specific guidelines are suggested to cover peculiar situations or to comply with other associated analytical methods.