title: Susceptibility of Phelipanche and Orobanche species to AAL-toxin.
abstract: Fusarium and Alternaria spp. are phytopathogenic fungi which are known to be virulent on broomrapes and to produce sphinganine-analog mycotoxins (SAMs). AAL-toxin is a SAM produced by Alternaria alternata which causes the inhibition of sphinganine N-acyltransferase, a key enzyme in sphingolipid biosynthesis, leading to accumulation of sphingoid bases. These long chain bases (LCBs) are determinant in the occurrence of programmed cell death (PCD) in susceptible plants. We showed that broomrapes are sensitive to AAL-toxin, which is not common plant behavior, and that AAL-toxin triggers cell death at the apex of the radicle as well as LCB accumulation and DNA laddering. We also demonstrated that three Lag1 homologs, encoding components of sphinganine N-acyltransferase in yeast, are present in the Orobanche cumana genome and two of them are mutated leading to an enhanced susceptibility to AAL-toxin. We therefore propose a model for the molecular mechanism governing broomrape susceptibility to the fungus Alternaria alternata.
authors.affiliation: Laboratoire de Biologie et Pathologie Végétales, EA 1157, IFR 149 QUASAV, Université de Nantes, 44322 Nantes cedex 3, France.
authors.forename: Axel
authors.initials: A
authors.lastname: de Zélicourt
authors.forename: Grégory
authors.initials: G
authors.lastname: Montiel
authors.forename: Jean-Bernard
authors.initials: JB
authors.lastname: Pouvreau
authors.forename: Séverine
authors.initials: S
authors.lastname: Thoiron
authors.forename: Sabine
authors.initials: S
authors.lastname: Delgrange
authors.forename: Philippe
authors.initials: P
authors.lastname: Simier
authors.forename: Philippe
authors.initials: P
authors.lastname: Delavault
mesh_terms: D000595:Amino Acid Sequence; D016923:Cell Death / Q000187:drug effects; D003001:Cloning, Molecular; D053938:DNA Fragmentation / Q000187:drug effects; D018525:Germination / Q000187:drug effects; D008969:Molecular Sequence Data; D031670:Orobanchaceae / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology; D031672:Orobanche / Q000166:cytology / Q000187:drug effects* / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D036226:Seedlings / Q000166:cytology / Q000187:drug effects / Q000382:microbiology; D012639:Seeds / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013110:Sphingosine / Q000633:toxicity*
chemical_list: C047996:Alternaria alternata pathotoxin TA; D010940:Plant Proteins; D013110:Sphingosine
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