Lipid signalling mediated by PLD/PA modulates proline and HO levels in barley seedlings exposed to short- and long-term chilling stress.

Phospholipase D (PLD) hydrolyses phospholipids to yield phosphatidic acid (PA) and a head group, and is involved in responses to a variety of environmental stresses, including chilling and freezing stress. Barley responses to chilling stress (induced by incubating seedlings at 4 °C) are dynamic and the duration of stress, either short (0-180 min) or long-term (24-36 h) had a significant impact on the response. We investigated the roles of PLD/PA in responses of barley (Hordeum vulgare) seedlings to short and long-term chilling stress, based on regulation of proline and reactive oxygen species (ROS) levels.

Comparative phytohormone profiles, lipid kinase and lipid phosphatase activities in barley aleurone, coleoptile, and root tissues.

We analyzed lipid kinase and lipid phosphatase activities and determined endogenous phytohormone levels by liquid chromatography-tandem mass spectrometry in root and coleoptile tissues following germination of barley (Hordeum vulgare) seeds. The enzymes showing highest activity in aleurone cells were diacylglycerol kinase (DAG-k, EC 2.7.