title: Identification and Characterization of Plant Cell Death-Inducing Secreted Proteins From Ustilaginoidea virens.
abstract: Ustilaginoidea virens (Cooke) Takah (telemorph Villosiclava virens) is an ascomycetous fungus that causes rice false smut, one of the most important rice diseases. Fungal effectors often play essential roles in host-pathogen coevolutionary interactions. However, little is known about the functions of U. virens effectors. Here, we performed functional studies on putative effectors in U. virens and demonstrated that 13 of 119 putative effectors caused necrosis or necrosis-like phenotypes in Nicotiana benthamiana. Among them, 11 proteins were confirmed to be secreted, using a yeast secretion system, and the corresponding genes are all highly induced during infection, except UV_44 and UV_4753. Eight secreted proteins were proven to trigger cell death or defenses in rice protoplasts and the secretion signal of these proteins is essential for their cell death-inducing activity. The ability of UV_44 and UV_1423 to trigger cell death is dependent on the predicted serine peptidase and ribonuclease catalytic active sites, respectively. We demonstrated that UV_1423 and UV_6205 are N-glycosylated proteins, which glycosylation has different impacts on their abilities to induce cell death. Collectively, the study identified multiple secreted proteins in U. virens with specific structural motifs that induce cell death or defense machinery in nonhost and host plants.
authors.affiliation: Department of Plant Pathology; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors.forename: Anfei
authors.initials: A
authors.lastname: Fang
authors.affiliation: Department of Plant Pathology; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Han
authors.affiliation: Department of Plant Pathology; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Department of Plant Pathology; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Plant Pathology; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Plant Pathology; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Plant Pathology; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors.forename: Fen
authors.initials: F
authors.lastname: Lu
authors.affiliation: Department of Plant Pathology; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors.forename: Wenxian
authors.initials: W
authors.lastname: Sun
mesh_terms: D001203:Ascomycota / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D020134:Catalytic Domain; D016923:Cell Death; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D015966:Gene Expression Regulation, Fungal / Q000502:physiology; D012275:Oryza / Q000166:cytology*; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology; D011523:Protoplasts; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology*; D014774:Virulence
chemical_list: D005656:Fungal Proteins; D012260:Ribonucleases