A Protein Kinase Target of a PDK1 Signaling Pathway Is Involved in Root Hair Growth in Arabidopsis

The study identified the protein kinase AGC2-1 as a target of the AtPDK1 signaling pathway in Arabidopsis, playing a crucial role in root hair growth. AtPDK1 regulated AGC2-1 through phosphatidic acid, which activated AGC2-1 in an AtPDK1-dependent manner. The activation of AGC2-1 was further enhanced by the plant hormones auxin and cytokinin. AGC2-1 was abundant in fast-growing and dividing tissues, and its knockout mutation led to significantly shorter root hairs, indicating its essential role in root hair development. This research contributed to understanding lipid signaling pathways in plants, particularly concerning root hair growth.