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

The study explores the role of the receptor-like kinase CAP1 in Arabidopsis thaliana under ammonium (NH4+) stress, revealing that CAP1 promotes shoot growth by mitigating NH4+ toxicity. The cap1-1 mutant, lacking CAP1, exhibited smaller shoots and higher reactive oxygen species (ROS) levels compared to the wild type under NH4+ stress. This was linked to altered expression of respiratory burst oxidase homologue and catalase genes. CAP1 helps maintain cell wall extensibility and ROS homeostasis, crucial for shoot growth under NH4+ stress. Transgenic lines expressing CAP1 in the cap1-1 background restored normal growth, confirming CAP1's role in mitigating NH4+ hypersensitivity. The study involved sample sizes ranging from 8 to 33 for different tests.