XVI International Botanical Congess

It is unclear how cell-cell transport via plasmodesmata is regulated, but the recent discovery of actin and myosin in plasmodesmata suggests a role for actomyosin. We examined the effects of actin and myosin inhibitors on cell-cell dye transport in A. thaliana root tips and T. virginiana staminal hairs. All experiments were conducted with or without DDG, which prevents reduction in cell-cell transport caused by microinjection-induced callose synthesis. The myosin inhibitor NEM and anti-myosin antibodies reduced cell-cell transport between root epidermal cells but increased transport between the stamen hairs, whereas the myosin inhibitor BDM had the opposite effects. Injection of calcium or ATPgS transiently inhibited transport in both systems. The actin microfilament disrupters cytochalasin D and latrunculin B had no effect on cell-cell transport in either system.