Breakthrough Technologies: Hydroxyproline-rich glycoproteins – bioinformatics and evolution

A pair of Breakthrough Technology papers in Plant Physiology discusses new tools to identify hydroxyproline-rich glycoproteins and insights into their evolution. Hydroxyproline-rich glycoproteins (HRGPs) are repeat-rich cell wall proteins that have been described as falling into three large families: arabinogalactan-proteins (AGPs), extensins (EXTs), and proline-rich proteins (PRPs).  In the first paper (10.1104/pp.17.00294), Johnson et al. describe a motif and amino acid bias (MAAB) approach to classify HRGPs, which they now describe as falling into 23 sub-classes. Using these insights, Johnson et al. (10.1104/pp.17.00295) examine the phylogenetic distribution and evolution of HRGPs using data from the 1000 plant transcriptome project (  They also describe the many remaining challenges to understand the contributions of these diverse proteins to cell wall structure and function. Plant Physiol.