title: Germination and infectivity of microconidia in the rice blast fungus Magnaporthe oryzae.
abstract: The rice blast fungus Magnaporthe oryzae is a model for studying fungal-plant interactions. Although it produces two types of spores (microconidia and macroconidia), previous infection studies have exclusively dealt with macroconidia. Germination of microconidia has not been reported, and their role in plant infection is not defined. Here we show that approximately 10% of microconidia germinate on plant surfaces, and that colonies derived from germinated microconidia are normal in growth and pathogenesis. In infection assays with rice and barley seedlings, microconidia fail to infect intact plants, but they can colonize and develop necrotic lesions on wounded leaves and stems. Microconidia also cause disease symptoms on inoculated spikelets in infection assays with barley and Brachypodium heads. Furthermore, microconidia are detected inside rice plants that developed blast lesions under laboratory or field conditions. Therefore, microconidia can germinate and are infectious, and may be an important factor in the rice blast cycle.
authors.affiliation: 1] State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China [2] Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA [3].
authors.forename: Huili
authors.initials: H
authors.lastname: Zhang
authors.affiliation: 1] State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China [2].
authors.forename: Zhongshou
authors.initials: Z
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Chenfang
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: 1] State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China [2] Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Jin-Rong
authors.initials: JR
authors.lastname: Xu
mesh_terms: D058431:Brachypodium / Q000382:microbiology; D015870:Gene Expression; D005800:Genes, Fungal; D001467:Hordeum / Q000382:microbiology; D054884:Host-Pathogen Interactions; D020082:Magnaporthe / Q000235:genetics / Q000472:pathogenicity* / Q000648:ultrastructure; D012275:Oryza / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology*; D018547:Plant Stems / Q000382:microbiology*; D013172:Spores, Fungal / Q000235:genetics / Q000472:pathogenicity* / Q000648:ultrastructure
references.citation: PLoS Pathog. 2012 Sep;8(9):e1002911
references.pmid: 22969430
references.citation: Curr Opin Plant Biol. 2010 Aug;13(4):434-41
references.pmid: 20627803
references.citation: Nature. 2004 Sep 30;431(7008):582-6
references.pmid: 15457264
references.citation: Curr Opin Microbiol. 2012 Dec;15(6):678-84
references.pmid: 23085322
references.citation: PLoS Pathog. 2011 Jan 20;7(1):e1001261
references.pmid: 21283781
references.citation: Annu Rev Phytopathol. 2007;45:437-56
references.pmid: 17489691
references.citation: Plant Cell. 2000 Sep;12(9):1703-18
references.pmid: 11006342
references.citation: Mol Microbiol. 2011 Apr;80(1):33-53
references.pmid: 21276092
references.citation: Nature. 2005 Apr 21;434(7036):980-6
references.pmid: 15846337
references.citation: Eukaryot Cell. 2008 May;7(5):791-9
references.pmid: 18344407
references.citation: Nature. 2004 Sep 30;431(7008):516-7
references.pmid: 15457240
references.citation: Plant Cell. 2010 Sep;22(9):3177-87
references.pmid: 20858844
references.citation: Mol Plant Pathol. 2012 May;13(4):414-30
references.pmid: 22471698
references.citation: Fungal Genet Biol. 1999 Feb;26(1):1-18
references.pmid: 10072316
references.citation: New Phytol. 2009 Oct;184(2):473-484
references.pmid: 19645735
references.citation: PLoS Pathog. 2012 Feb;8(2):e1002526
references.pmid: 22346755
references.citation: Plant Cell Physiol. 2007 Aug;48(8):1219-28
references.pmid: 17634180
references.citation: Proc Natl Acad Sci U S A. 2009 Sep 15;106(37):15967-72
references.pmid: 19717456
references.citation: Nat Commun. 2013;4:1996
references.pmid: 23774898
references.citation: Nat Protoc. 2008;3(3):435-45
references.pmid: 18323815
references.citation: Planta. 2007 May;225(6):1381-91
references.pmid: 17143617
references.citation: Mol Microbiol. 2004 Sep;53(6):1695-707
references.pmid: 15341648
references.citation: Genome Res. 1997 Oct;7(10):986-95
references.pmid: 9331369
references.citation: Eukaryot Cell. 2007 Jun;6(6):997-1005
references.pmid: 17416896
references.citation: Nat Rev Microbiol. 2009 Mar;7(3):185-95
references.pmid: 19219052
references.citation: Eukaryot Cell. 2007 Oct;6(10):1701-14
references.pmid: 17715363