Search for: All records

Actin filament assembly in plants is a dynamic process, requiring the activity of more than 75 actin‐binding proteins. Central to the regulation of filament assembly and stability is the activity of a conserved family of actin‐depolymerizing factors (ADFs), whose primarily function is to regulate the severing and depolymerization of actin filaments. In recent years, the activity ofADFproteins has been linked to a variety of cellular processes, including those associated with response to stress. Herein, a wheatADFgene,TaADF4,was identified and characterized.TaADF4encodes a 139‐amino‐acid protein containing five F‐actin‐binding sites and two G‐actin‐binding sites, and interacts with wheat (Triticum aestivum) Actin1 (TaACT1),in planta. Following treatment of wheat, separately, with jasmonic acid, abscisic acid or with the avirulent race,CYR23, of the stripe rust pathogenPuccinia striiformisf. sp.tritici, we observed a rapid induction in accumulation ofTaADF4mRNA. Interestingly, accumulation ofTaADF4mRNAwas diminished in response to inoculation with a virulent race,CYR31. Silencing ofTaADF4resulted in enhanced susceptibility toCYR23, demonstrating a role forTaADF4in defense signaling. Using a pharmacological‐based approach, coupled with an analysis of host response to pathogen infection, we observed that treatment of plants with the actin‐modifying agent latrunculin B enhanced resistance toCYR23, including increased production of reactive oxygen species and enhancement of localized hypersensitive cell death. Taken together, these data support the hypothesis thatTaADF4 positively modulates plant immunity in wheat via the modulation of actin cytoskeletal organization.