title: Functional characterization of calcineurin homologs PsCNA1/PsCNB1 in Puccinia striiformis f. sp. tritici using a host-induced RNAi system.
abstract: Calcineurin plays a key role in morphogenesis, pathogenesis and drug resistance in most fungi. However, the function of calcineurin genes in Puccinia striiformis f. sp. tritici (Pst) is unclear. We identified and characterized the calcineurin genes PsCNA1 and PsCNB1 in Pst. Phylogenetic analyses indicate that PsCNA1 and PsCNB1 form a calcium/calmodulin regulated protein phosphatase belonging to the calcineurin heterodimers composed of subunits A and B. Quantitative RT-PCR analyses revealed that both PsCNA1 and PsCNB1 expression reached their maximum in the stage of haustorium formation, which is one day after inoculation. Using barely stripe mosaic virus (BSMV) as a transient expression vector in wheat, the expression of PsCNA1 and PsCNB1 in Pst was suppressed, leading to slower extension of fungal hyphae and reduced production of urediospores. The immune-suppressive drugs cyclosporin A and FK506 markedly reduced the germination rates of urediospores, and when germination did occur, more than two germtubes were produced. These results suggest that the calcineurin signaling pathway participates in stripe rust morphogenetic differentiation, especially the formation of haustoria during the early stage of infection and during the production of urediospores. Therefore PsCNA1 and PsCNB1 can be considered important pathogenicity genes involved in the wheat-Pst interaction.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A & F University, Yangling, Shaanxi, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
authors.forename: Ralf T
authors.initials: RT
authors.lastname: Voegele
authors.forename: Jinshan
authors.initials: J
authors.lastname: Zhang
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Duan
authors.forename: Huaiyong
authors.initials: H
authors.lastname: Luo
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Kang
mesh_terms: D001487:Basidiomycota / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D019703:Calcineurin / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal / Q000235:genetics; D016153:Genes, Suppressor; D054884:Host-Pathogen Interactions / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D018515:Plant Leaves / Q000382:microbiology; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000502:physiology; D014908:Triticum / Q000382:microbiology
chemical_list: D005656:Fungal Proteins; D012333:RNA, Messenger; D019703:Calcineurin