title: Unconventionally secreted effectors of two filamentous pathogens target plant salicylate biosynthesis.
abstract: Plant diseases caused by fungi and oomycetes pose an increasing threat to food security and ecosystem health worldwide. These filamentous pathogens, while taxonomically distinct, modulate host defense responses by secreting effectors, which are typically identified based on the presence of signal peptides. Here we show that Phytophthora sojae and Verticillium dahliae secrete isochorismatases (PsIsc1 and VdIsc1, respectively) that are required for full pathogenesis. PsIsc1 and VdIsc1 can suppress salicylate-mediated innate immunity in planta and hydrolyse isochorismate in vitro. A conserved triad of catalytic residues is essential for both functions. Thus, the two proteins are isochorismatase effectors that disrupt the plant salicylate metabolism pathway by suppressing its precursor. Furthermore, these proteins lack signal peptides, but exhibit characteristics that lead to unconventional secretion. Therefore, this secretion pathway is a novel mechanism for delivering effectors and might play an important role in host-pathogen interactions.
authors.affiliation: 1] Department of Plant Pathology, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China [2] Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing 210095, China [3].
authors.forename: Tingli
authors.initials: T
authors.lastname: Liu
authors.affiliation: 1] Department of Plant Pathology, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China [2].
authors.forename: Tianqiao
authors.initials: T
authors.lastname: Song
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China.
authors.forename: Xiong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing 210095, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Su
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China.
authors.forename: Wanlin
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China.
authors.forename: Shiheng
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China.
authors.forename: Linlin
authors.initials: L
authors.lastname: Chen
authors.affiliation: Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing 210095, China.
authors.forename: Tianzi
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China.
authors.forename: Meixiang
authors.initials: M
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China.
authors.forename: Lichuan
authors.initials: L
authors.lastname: Gu
authors.affiliation: Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing 210095, China.
authors.forename: Baolong
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China.
authors.forename: Daolong
authors.initials: D
authors.lastname: Dou
mesh_terms: D020134:Catalytic Domain; D005656:Fungal Proteins / Q000378:metabolism; D003368:Gossypium / Q000382:microbiology / Q000502:physiology; D054884:Host-Pathogen Interactions; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism*; D030781:Organisms, Genetically Modified; D010838:Phytophthora / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D010935:Plant Diseases / Q000382:microbiology; D021381:Protein Transport; D012459:Salicylates / Q000378:metabolism*; D020172:Verticillium / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D012459:Salicylates; D037521:Virulence Factors; D006867:Hydrolases; C064012:isochorismatase