title: An extracellular Zn-only superoxide dismutase from Puccinia striiformis confers enhanced resistance to host-derived oxidative stress.
abstract: Accumulation of reactive oxygen species (ROS) following plant-pathogen interactions can trigger plant defence responses and directly damage pathogens. Thus, it is essential for pathogens to scavenge host-derived ROS to establish a parasitic relationship. However, the mechanisms protecting pathogens from host-derived oxidative stress remain unclear. In this study, a superoxide dismutase (SOD) gene, PsSOD1, was cloned from a wheat-Puccinia striiformis f. sp. tritici (Pst) interaction cDNA library. Transcripts of PsSOD1 were up-regulated in the early infection stage. Heterologous mutant complementation and biochemical characterization revealed that PsSOD1 encoded a Zn-only SOD. The predicted signal peptide was functional in an invertase-mutated yeast strain. Furthermore, immunoblot analysis of apoplastic proteins in Pst-infected wheat leaves and bimolecular fluorescence complementation suggested that PsSOD1 is a secreted protein that potentially forms a dimer during Pst infection. Overexpression of PsSOD1 enhanced Schizosaccharomyces pombe resistance to exogenous superoxide. Transient expression of PsSOD1 in Nicotiana benthamiana suppressed Bax-induced cell death. Knockdown of PsSOD1 using a host-induced gene silencing (HIGS) system reduced the virulence of Pst, which was associated with ROS accumulation in HIGS plants. These results suggest that PsSOD1 is an important pathogenicity factor that is secreted into the host-pathogen interface to contribute to Pst infection by scavenging host-derived ROS.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Guan
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Peijing
authors.initials: P
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Liyang
authors.initials: L
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Baoyu
authors.initials: B
authors.lastname: Huai
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Chang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Lili
authors.initials: L
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People's Republic of China.
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Kang
mesh_terms: D001487:Basidiomycota / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018384:Oxidative Stress; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D014026:Nicotiana / Q000382:microbiology; D014908:Triticum / Q000382:microbiology; D014774:Virulence; D015032:Zinc / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D015032:Zinc