title: Threonine deaminase MoIlv1 is important for conidiogenesis and pathogenesis in the rice blast fungus Magnaporthe oryzae.
abstract: Threonine deaminase is the first critical enzyme in the biosynthesis of branched-chain amino acids (BCAAs), which catalyzes threonine into NH2 and ketobutyrate acid. Previously, we identified and characterized two acetolactate synthases MoIlv2 and MoIlv6 that are involved in the second step of BCAA biosynthesis. Deletion of MoILV2 and MoILV6 resulted in auxotrophy for leucine, isoleucine, and valine and defects in conidiation, appressorial penetration, and pathogenicity. Here, we identified a threonine dehydratase, named MoIlv1, from Magnaporthe oryzae. MoIlv1 is a homolog of Saccharomyces cerevisiae Ilv1p, which has an important role in the biosynthesis of isoleucine. To characterize the function of MoIlv1, a ΔMoilv1 knock-out mutant was generated and analyzed. Disruption of MoILV1 resulted in abnormal conidial morphology, reduced conidiation, limited appressorium-mediated penetration, and attenuated virulence on both barley and rice seedlings. Further analysis by domain-specific deletion revealed that the PALP domain is indispensable for MoIlv1 function. Our study indicates that MoIlv1 is a protein involved in isoleucine biosynthesis that underlies the complex process governing morphogenesis, appressorium formation, invasive hyphae growth, and pathogenicity.
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Du
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
authors.forename: Li
authors.initials: L
authors.lastname: Hong
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Tang
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
authors.forename: Lianwei
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Ma
authors.affiliation: State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Zhengyi
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China. Electronic address: hfzhang@njau.edu.cn.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
authors.forename: Zhengguang
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D055786:Gene Knockout Techniques; D001467:Hordeum / Q000382:microbiology; D025301:Hyphae / Q000254:growth & development / Q000378:metabolism; D007532:Isoleucine / Q000378:metabolism; D020082:Magnaporthe / Q000472:pathogenicity* / Q000502:physiology; D012275:Oryza / Q000382:microbiology*; D013172:Spores, Fungal / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D013913:Threonine Dehydratase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014774:Virulence / Q000502:physiology
chemical_list: D005656:Fungal Proteins; D007532:Isoleucine; D013913:Threonine Dehydratase
keywords: Conidiogenesis; Magnaporthe oryzae; MoIlv1; Pathogenesis; Threonine deaminase