Ancient roots of phytohormone signalling
The plant hormone auxin plays a key role in the formation of individual plant organs, the coordination of growth and fundamentally influences the life cycle of the plant. Auxin is known to trigger both rapid and slow cellular responses in plants and algae. However, while in plants auxin controls growth and gene expression by a nuclear auxin pathway, this form of signalling is absent in algae. A new study has discovered a rapid proteome-wide phosphorylation response to auxin that occurs both in land plants and algae. So-called RAF-like protein kinases play a central role in mediating this auxin-triggered phosphorylation, revealing an ancient mechanism for fast auxin responses in the green lineage.
The original study is online here