The Arabidopsis Receptor-Like Kinase CAP1 Promotes Shoot Growth Under Ammonium Stress

The study investigates the role of the receptor-like kinase CAP1 in Arabidopsis thaliana under ammonium (NH4+) stress, which typically inhibits plant growth. The research reveals that CAP1 not only regulates root hair growth but also promotes shoot growth by mitigating NH4+ toxicity. The cap1-1 mutant, lacking functional CAP1, exhibited smaller shoots and epidermal cells, increased reactive oxygen species (ROS) levels, and altered gene expression related to cell enlargement and ROS management compared to the wild type. These findings suggest that CAP1 enhances shoot growth under NH4+ stress by improving cell wall extensibility and maintaining ROS homeostasis, indicating its significant role in the NH4+ signal transduction pathway.