Salt stress-accelerated proteasomal degradation of LBD11 suppresses ROS-mediated meristem development and root growth in Arabidopsis

Roots absorb water and nutrients from the soil, support the plant's aboveground organs, and detect environmental changes, making them crucial targets for improving crop productivity. Roots are particularly sensitive to soil salinity, a major abiotic stress that poses a serious threat to global agriculture. In response to salt stress, plants suppress root meristem size, thus reducing root growth; however, the mechanisms underlying this growth restriction remain unclear. Here, we explore the role of reactive oxygen species (ROS) in this process, reveal that LATERAL ORGAN BOUNDARIES DOMAIN 11 (LBD11) plays a central role in the ROS-mediated regulation of meristem size and the salt stress-induced inhibition of root growth. Under normal conditions, LBD11 governs the expression of key ROS metabolic genes, maintaining ROS homeostasis within root developmental zones to control meristem size and overall root growth. Upon sensing salt stress, LBD11 undergoes rapid proteasome-mediated degradation, leading to decreased O