Phenylpropanoid biosynthesis in streptophyte algae
The phenylpropanoid pathway generates many of the signature molecules of land plants, including several defense compounds and the “wood” molecule, lignin. de Vries et al. (on pp. 934-945) report that the genetic toolkit for the biosynthesis of phenylpropanoids and lignin precursors was already present in streptophyte algae – the closest relatives of land plants. Their data help explain the observation that streptophyte algae have lignin-like compounds and suggest that streptophyte algal immunity includes phenylpropanoid-derived metabolites. These findings impact current views on how the first land plants acquired the ability to reinforce their cell walls and respond to pathogens.
The cover image shows a Nomarski micrograph of the streptophyte alga Coleochaete scutata, a close relative of Coleochaete orbicularis. The image was taken by Jan de Vries (Dalhousie University).