title: Wheat Stripe Rust Resistance Protein WKS1 Reduces the Ability of the Thylakoid-Associated Ascorbate Peroxidase to Detoxify Reactive Oxygen Species.
abstract: Stripe rust is a devastating fungal disease of wheat caused by Puccinia striiformis f. sp tritici (Pst). The WHEAT KINASE START1 (WKS1) resistance gene has an unusual combination of serine/threonine kinase and START lipid binding domains and confers partial resistance to Pst. Here, we show that wheat (Triticum aestivum) plants transformed with the complete WKS1 (variant WKS1.1) are resistant to Pst, whereas those transformed with an alternative splice variant with a truncated START domain (WKS1.2) are susceptible. WKS1.1 and WKS1.2 preferentially bind to the same lipids (phosphatidic acid and phosphatidylinositol phosphates) but differ in their protein-protein interactions. WKS1.1 is targeted to the chloroplast where it phosphorylates the thylakoid-associated ascorbate peroxidase (tAPX) and reduces its ability to detoxify peroxides. Increased expression of WKS1.1 in transgenic wheat accelerates leaf senescence in the absence of Pst. Based on these results, we propose that the phosphorylation of tAPX by WKS1.1 reduces the ability of the cells to detoxify reactive oxygen species and contributes to cell death. This response takes several days longer than typical hypersensitive cell death responses, thus allowing the limited pathogen growth and restricted sporulation that is characteristic of the WKS1 partial resistance response to Pst.
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616 State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China.
authors.forename: Jin-Ying
authors.initials: JY
authors.lastname: Gou
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616 State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616.
authors.forename: Kati
authors.initials: K
authors.lastname: Wu
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616.
authors.forename: Huiqiong
authors.initials: H
authors.lastname: Lin
authors.affiliation: Department of Viticulture and Enology, University of California, Davis, California 95616.
authors.forename: Dario
authors.initials: D
authors.lastname: Cantu
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom National Institute of Agricultural Botany, Cambridge CB3 0LE, United Kingdom.
authors.forename: Cristobal
authors.identifier: http://orcid.org/0000-0002-9814-1770
authors.initials: C
authors.lastname: Uauy
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom.
authors.forename: Albor
authors.initials: A
authors.lastname: Dobon-Alonso
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616.
authors.forename: Takamufi
authors.initials: T
authors.lastname: Midorikawa
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Inoue
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616.
authors.forename: Juan
authors.initials: J
authors.lastname: Sánchez
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Daolin
authors.initials: D
authors.lastname: Fu
authors.affiliation: U.S. Department of Agriculture-Agricultural Research Service, Western Regional Research Center, Albany, California 94710.
authors.forename: Ann
authors.initials: A
authors.lastname: Blechl
authors.affiliation: National Institute of Agricultural Botany, Cambridge CB3 0LE, United Kingdom.
authors.forename: Emma
authors.initials: E
authors.lastname: Wallington
authors.affiliation: Institute of Evolution and the Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 31905, Israel.
authors.forename: Tzion
authors.initials: T
authors.lastname: Fahima
authors.affiliation: Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana 141004, Punjab, India.
authors.forename: Madhu
authors.initials: M
authors.lastname: Meeta
authors.affiliation: Department of Plant Pathology, University of California, Davis, California 95616.
authors.forename: Lynn
authors.initials: L
authors.lastname: Epstein
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616 Howard Hughes Medical Institute, Chevy Chase, Maryland 20815 jdubcovsky@ucdavis.edu.
authors.forename: Jorge
authors.identifier: http://orcid.org/0000-0002-7571-4345
authors.initials: J
authors.lastname: Dubcovsky
mesh_terms: D060387:Ascorbate Peroxidases / Q000378:metabolism / Q000502:physiology*; D001487:Basidiomycota / Q000472:pathogenicity / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020524:Thylakoids / Q000201:enzymology* / Q000378:metabolism; D014908:Triticum / Q000382:microbiology* / Q000502:physiology
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; D060387:Ascorbate Peroxidases