TaADF7, an actin‐depolymerizing factor, contributes to wheat resistance against Puccinia striiformis f. sp. tritici

• Published in: The Plant journal : for cell and molecular biology 2014-04, Vol.78 (1), p.16-30
• Main Authors: Fu, Yanping, Duan, Xiaoyuan, Tang, Chunlei, Li, Xiaorui, Voegele, Ralf T., Wang, Xiaojie, Wei, Guorong, Kang, Zhensheng
• Format: Article
• Language: English
• Subjects: actin cytoskeleton; Actin Cytoskeleton - genetics; Actin Cytoskeleton - metabolism; actin‐depolymerizing factor; Amino Acid Sequence; Base Sequence; Basidiomycota - physiology; Crop diseases; Cytoskeleton; Destrin - genetics; Destrin - metabolism; Disease Resistance; Gene Expression; Gene Expression Regulation, Plant; Gene Knockdown Techniques; Gene Silencing; Host-Pathogen Interactions; Molecular Sequence Data; Nicotiana - genetics; Nicotiana - metabolism; Plant Diseases - immunology; Plant Leaves - cytology; Plant Leaves - genetics; Plant Leaves - immunology; Plant pathology; Plant Proteins - genetics; Plant Proteins - metabolism; Plant resistance; Plants, Genetically Modified; Puccinia striiformis; Puccinia striiformis f. sp. tritici; Reactive Oxygen Species - metabolism; Sequence Analysis, DNA; Triticum - cytology; Triticum - genetics; Triticum - immunology; Triticum aestivum; virus‐induced gene silencing; Wheat
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.12457

Summary The actin cytoskeleton is involved in plant defense responses; however, the role of the actin‐depolymerizing factor (ADF) family, which regulates actin cytoskeletal dynamics, in plant disease resistance, is largely unknown. Here, we characterized a wheat (Triticum aestivum) ADF gene, TaADF7, with three copies located on chromosomes 1A, 1B, and 1D, respectively. All three copies encoded the same protein, although there were variations in 19 nucleotide positions in the open reading frame. Transcriptional expression of the three TaADF7 copies were all sharply elevated in response to avirulent Puccinia striiformis f. sp. tritici (Pst) infection, with similar expression patterns. TaADF7 regulated the actin cytoskeletal dynamics by targeting the actin cytoskeleton to execute actin binding/severing activities. When the TaADF7 copies were all silenced by virus‐induced gene silencing, the growth of Pst hypha increased and sporadic urediniospores were observed, as compared with control plants, upon inoculation with avirulent Pst. In addition, the accumulation of reactive oxygen species (ROS) and the hypersensitive response (HR) were greatly weakened, whereas cytochalasin B partially rescued the HR in TaADF7 knock‐down plants. Together, these findings suggest that TaADF7 is likely to contribute to wheat resistance against Pst infection by modulating the actin cytoskeletal dynamics to influence ROS accumulation and the HR.