Current Challenges in Plant Cell Walls: Editorial Overview

Abstract

composition of the plant cell wall. Here, powerful MS methods are detailed for the elucidation of the structure of oligosaccharides derived from hemicelluloses and pectins. The author illustrates how information on sequence, linkages, branching, and modifications can be obtained from characteristic fragmentation patterns. This method is of further note when combined with molecular genetics (mutant analysis) to elucidate the function of a target gene.Global transcript analyses based on a wealth of available micro-array datasets have revealed that genes that are in the same pathway are often transcribed in a coordinate manner. Here Ruprecht and Persson (2012) have summarized recent developments in software as well as combining transcriptional data from multiple plant spe-cies to learn about how particular cell wall processes are different, rather than the same. This exciting update provides successful examples of where expression profiling has helped to identify genes involved in the formation of cellulose, hemicelluloses, and lignin. In addition, they illustrate potential pitfalls and future perspectives. The broad employment of next generation sequencing for RNAseq experiments will surely expand the available data (as not all coding sequences are represented on a given microarray chip). This will require some software refinement, but also see further gains result-ing from coexpression profiling in the near future. The use of deep sequencing platforms like Illumina’s Genome Analyzer or ABI’s SOLiD was reviewed by Vidaurre and Bonetta (2012) in the context of map based cloning. Here, a path to rapidly accelerating forward genetics in the context of cell wall biosynthesis and deconstruc-tion was paved. Anyone who has laboriously mapped a missense mutation will greatly appreciate the ability to pinpoint a mutation selected from within an EMS (ethyl methyl suflonate) population in a single sequencing run. This combination of a classical genet-ics approach and cutting edge technology can holds immediate promise for gene identification.To assemble plant cell wall polysaccharides and glycan structures on glycoproteins, the plant needs extensive biosynthetic machin-ery, and it has been estimated that over 2000 gene products are involved in making and maintaining the wall. The Carbohydrate Active Enzyme (CAZy) database is an invaluable resource for glyco-biology and currently contains 45 glycosyltransferase (GT) families that are represented in plants. Hansen et al. (2012) describe the putative GTs that are not currently classified in the CAZy database. These families include proteins with domain of unknown func-tion (DUF). The evidence for certain members of the DUF class proteins being GTs and their possible roles in cell wall biosynthesis are discussed.