Arabidopsis thaliana plants lacking the ARP2/3 complex show defects in cell wall assembly and auxin distribution

The plant cytoskeleton determines cell shape and integrity by delivering cellulose microfibrils and other cell wall components to the plasma membrane and cell wall. Auxin is involved in establishing the polarity of cell expansion and auxin distribution is partly regulated by actin. Sahi et al. examine the role of ARP2/3 in connecting F-actin dynamics and auxin distribution during cell wall synthesis. Actin nucleation involves the ARP2/3 protein complex and arp2/3 mutants in epidermal cotyledon cells resulted in less lobed cells (increased cell circularity) and cell-cell adhesion defects between epidermal-epidermal and epidermal-guard cells. The arp2/3 mutants also displayed decreased cell wall thickness, altered cellulose content, and reduced auxin transport. These data indicate that ARP2/3 plays a role in controlling cell wall synthesis and auxin transport (Summary by Alecia Biel) Annals of Botany. 10.1093/aob/mcx178.