Auxin signaling gets oxidative to promote root hair growth

Abstract

Root hairs (RHs) emerge as cylindrical cell protrusions from the root epidermis in a polar manner, and these outgrows increase the rhizosphere space to acquire water and nutrients, anchor the plant, and interact with various soil microorganisms. Auxin is one of the key hormones to promote RH growth, and high levels of auxin are directly promoted by low levels of macronutrients in the soil, such as phosphate (Bhosale et al., 2018) and nitrates (Jia et al., 2023). The nutritional signals for roots, which rapidly change in both time and place within the soil, are tightly linked to signaling pathways that execute swifts on cellular processes to adjust to a challenging environment. Plant rapid alkalinization factors (RALFs) are peptides that are released outside the cell and act as peptide-hormone signals. They attach to the extracellular domains of members of the Catharanthus roseus RECEPTOR-LIKE KINASE 1-LIKE family, specifically FERONIA (FER) in conjunction with its co-receptor LORELEI-LIKE-GPIANCHORED PROTEIN 1. RALF1 and RALF22 have crucial roles in regulating RH growth and enable roots to adapt to changes in their environment, although the specific signals that activate their expression remain unknown (Zhu et al., 2020; Schoenaers et al., 2024). This peptide-receptor interaction, which is well known for RALF1-FER, triggers the activation of multiple downstream partners, including ErbB3-binding protein 1, RPM1-induced protein kinase, early translation factor eIF4E1, and target of rapamycin complex 1, among others. Several of these downstream components regulate RH growth and other plant developmental processes in a coordinated manner (Cheung 2024)...