title: Two distinct Ras genes from Puccinia striiformis exhibit differential roles in rust pathogenicity and cell death.
abstract: Ras genes have been shown to regulate a variety of cellular processes in higher eukaryotes. However, much less is known about their function(s) in fungi, especially plant pathogenic fungi. Here, we report the identification and functional analysis of Ras genes from Puccinia striiformis f. sp. tritici (Pst), an important fungal pathogen in wheat production worldwide. Pst contains two Ras genes, PsRas1 and PsRas2, which share 48.6% similarity at the protein level and fall into two different phylogenetic clades. Both PsRas1 and PsRas2 have conserved protein sequences among different Pst isolates, but exhibit different transcript profiles during Pst infection. Silencing of PsRas1 or PsRas2 indicates that PsRas2 but not PsRas1 contributes significantly to rust pathogenicity. However, overexpression of PsRas1, but not PsRas2, promotes cell death in yeast and plants. Further studies show that all conserved domains of Ras GTPases in PsRas1 are needed to induce this cell death. In plants, PsRas1-triggered cell death shows similar characteristics as plant hypersensitive response. Our findings suggest that PsRas1 and PsRas2 take over different functions in rust pathogenicity and cell death, thus facilitating the understanding of cell death, pathogenic mechanisms of plant pathogenic fungi and the search for novel pathogen control strategies.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
authors.forename: Yulin
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
authors.forename: Wumei
authors.initials: W
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
authors.forename: Juanni
authors.initials: J
authors.lastname: Yao
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
authors.forename: Lili
authors.initials: L
authors.lastname: Huang
authors.affiliation: Fachgebiet Phytopathologie, Fakultät Agrarwissenschaften, Institut für Phytomedizin, Universität Hohenheim, Stuttgart, Germany.
authors.forename: Ralf T
authors.initials: RT
authors.lastname: Voegele
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Kang
mesh_terms: D001487:Basidiomycota / Q000235:genetics / Q000472:pathogenicity*; D016923:Cell Death; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D014908:Triticum / Q000166:cytology / Q000382:microbiology*; D014774:Virulence; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D018631:ras Proteins