Actin Isovariant ACT7 Modulates Root Thermomorphogenesis by Altering Intracellular Auxin Homeostasis

High temperature stress is one of the most threatening abiotic stresses for plants limiting crop productivity world-wide. Altered developmental responses to moderate-high has been shown be linked intracellular auxin homeostasis regulated by both biosynthesis and transport. Trafficking carrier proteins plays a major role in maintaining cellular homeostasis. The trafficking largely relies on cytoskeletal component, actin, which provides track vesicle movement. Different classes actin isovariants function regulating various stages plant development. Although high alters trafficking, this process remains obscure. Using isovariant specific vegetative class mutants, here we demonstrate that ACTIN 7 (ACT7) an important response Arabidopsis root. Loss ACT7, but not ACT8 resulted increased inhibition root elongation under prolonged temperature. Consistently, kinematic analysis revealed drastic reduction cell production rate act7-4 mutant Quantification dynamicity reveals modulates bundling along with orientation parallelness filamentous mutant. hypersensitive was found altered distribution, from reduced abundance PIN-FORMED PIN1 PIN2 efflux carriers. Collectively, these results suggest isovariant, ACT7 long-term