title: An STE12 gene identified in the mycorrhizal fungus Glomus intraradices restores infectivity of a hemibiotrophic plant pathogen.
abstract: Mechanisms of root penetration by arbuscular mycorrhizal (AM) fungi are unknown and investigations are hampered by the lack of transformation systems for these unculturable obligate biotrophs. Early steps of host infection by hemibiotrophic fungal phytopathogens, sharing common features with those of AM fungal colonization, depend on the transcription factor STE12. Using degenerated primers and rapid amplification of cDNA ends, we isolated the full-length cDNA of an STE12-like gene, GintSTE, from Glomus intraradices and profiled GintSTE expression by real-time and in situ RT-PCR. GintSTE activity and function were investigated by heterologous complementation of a yeast ste12Delta mutant and a Colletotrichum lindemuthianum clste12Delta mutant. * Sequence data indicate that GintSTE is similar to STE12 from hemibiotrophic plant pathogens, especially Colletotrichum spp. Introduction of GintSTE into a noninvasive mutant of C. lindemuthianum restored fungal infectivity of plant tissues. GintSTE expression was specifically localized in extraradicular fungal structures and was up-regulated when G. intraradices penetrated roots of wild-type Medicago truncatula as compared with an incompatible mutant. Results suggest a possible role for GintSTE in early steps of root penetration by AM fungi, and that pathogenic and symbiotic fungi may share common regulatory mechanisms for invasion of plant tissues.
authors.affiliation: UMR INRA 1088/CNRS 5184/Université de Bourgogne, Plante-Microbe-Environnement, 17 Rue Sully - BP 86510 - 21065 Dijon Cedex, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Tollot
authors.forename: Joanne
authors.initials: J
authors.lastname: Wong Sak Hoi
authors.forename: Diederik
authors.initials: D
authors.lastname: van Tuinen
authors.forename: Christine
authors.initials: C
authors.lastname: Arnould
authors.forename: Odile
authors.initials: O
authors.lastname: Chatagnier
authors.forename: Bernard
authors.initials: B
authors.lastname: Dumas
authors.forename: Vivienne
authors.initials: V
authors.lastname: Gianinazzi-Pearson
authors.forename: Pascale M A
authors.initials: PM
authors.lastname: Seddas
mesh_terms: D000595:Amino Acid Sequence; D020231:Colletotrichum / Q000235:genetics / Q000472:pathogenicity*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D018525:Germination / Q000235:genetics; D055137:Glomeromycota / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D046913:Medicago truncatula / Q000382:microbiology*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D038821:Mycorrhizae / Q000235:genetics*; D027805:Phaseolus / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013172:Spores, Fungal / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D012333:RNA, Messenger