title: Functional conservation of wheat and rice Mlo orthologs in defense modulation to the powdery mildew fungus.
abstract: Homologs of barley Mlo are found in syntenic positions in all three genomes of hexaploid bread wheat, Triticum aestivum, and in rice, Oryza sativa. Candidate wheat orthologs, designated TaMlo-A1, TaMlo-B1, and TaMlo-D1, encode three distinct but highly related proteins that are 88% identical to barley MLO and appear to originate from the three diploid ancestral genomes of wheat. TaMlo-B1 and the rice ortholog, OsMlo2, are able to complement powdery mildew-resistant barley mlo mutants at the single-cell level. Overexpression of TaMlo-B1 or barley Mlo leads to super-susceptibility to the appropriate powdery mildew formae speciales in both wild-type barley and wheat. Surprisingly, overexpression of either Mlo or TaMlo-B1 also mediates enhanced fungal development to tested inappropriate formae speciales. These results underline a regulatory role for MLO and its wheat and rice orthologs in a basal defense mechanism that can interfere with forma specialis resistance to powdery mildews.
authors.affiliation: The Sainsbury Laboratory, John Innes Centre, Norwich, United Kingdom.
authors.forename: Candace
authors.initials: C
authors.lastname: Elliott
authors.forename: Fasong
authors.initials: F
authors.lastname: Zhou
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Spielmeyer
authors.forename: Ralph
authors.initials: R
authors.lastname: Panstruga
authors.forename: Paul
authors.initials: P
authors.lastname: Schulze-Lefert
mesh_terms: D000595:Amino Acid Sequence; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005658:Fungi / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant; D007113:Immunity, Innate / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000382:microbiology; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D026801:Synteny; D014908:Triticum / Q000235:genetics* / Q000382:microbiology
chemical_list: D018076:DNA, Complementary; C104922:MLO protein, Hordeum vulgare; D010940:Plant Proteins