Boronic acids as tools to study (plant) developmental processes?

Boron (B) is an essential micronutrient for organisms. In plants, B is known to stabilize the cell wall by crosslinking Rhamnogalacturonan II through ester bonds formed with cis-diols of sugar moieties. However, B is believed to be required for additional functions such as stability and function of (plasma membrane) proteins involved in signal transduction pathways. We have recently shown that boronic acids, competitors of B, efficiently induce perfect phenocopies of monopteros mutants. This effect is enigmatic because like B, boronic acids should find numerous cellular targets and thus disturb many biologic processes ending in a spectrum of unspecific embryo phenotypes. Based on chemical characteristics of boronic acids and their derivatives we discuss reasons that could explain this unusual specificity. The peculiarities of this class of compounds could provide new tools for studying developmental processes.