Synergistic deletion of RGS1 and COS1 may reduce the pathogenicity of Magnaporthe oryzae

  • He Na
  • An Bang
  • Xie Qing-biao
  • Yan Xia
  • Feng Hui-min
  • Luo Hong-li
  • He Chao-zuEmail author
Original Paper


Rice blast, caused by Magnaporthe oryzae, is a serious threat to global rice production. In recent years, many pathogenicity genes of M. oryzae have been identified, although most of their functions remain unknown. In this study, we report the synergistic deletion of RGS1 and COS1 that may reduce the pathogenicity of M. oryzae. The investigation involved comparing ΔMorgs1, ΔMocos1, and ΔMorgs1Mocos1 mutants. The ΔMorgs1Mocos1 mutant showed a weak reduction in vegetative growth, and the colonies displayed fewer and smoother aerial hyphae. The ΔMorgs1Mocos1 mutant exhibited delayed appressorium-like structure formation and ‘low pathogenicity’ on detached rice seedling leaves when compared with ΔMocos1. Moreover, the melanin content of the single and double mutants was remarkably lower than that of the WT type. Thus, our results indicate that the synergy between RGS1 and COS1 may be crucial in the pathogenicity of M. oryzae.


Magnaporthe oryzae Appressorium-like structure RGS1 Melanin 



Complete medium




Oatmeal agar


Quantitative reverse-transcription-polymerase chain reaction


Wild type



This work was supported by the National Natural Science Foundation of China (Grant no. 31260418).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. Bell AA, Wheeler MH (1986) Biosynthesis and functions of fungal melanins. Annu Rev Phytopathol 24:411–451CrossRefGoogle Scholar
  2. Chumley FG, Valent B (1990) Genetic analysis of melanin-deficient nonpathogenic mutants of Magnaporthe grisea. Mol Plant Microbe Interact 3:135–143CrossRefGoogle Scholar
  3. Eisenman HC, Casadevall A (2012) Synthesis and assembly of fungal melanin. Appl Microbiol Biotechnol 93:931–940CrossRefGoogle Scholar
  4. Fan R, Klosterman SJ, Wang C, Subbarao KV, Xu X, Shang W, Hu X (2017) Vayg1 is required for microsclerotium formation and melanin production in Verticillium dahliae. Fungal Genet Biol 98:1–11CrossRefGoogle Scholar
  5. Howard RJ, Valent B (1996) Breaking and entering: host penetration by the fungal rice blast pathogen Magnaporthe grisea. Annu Rev Microbiol 50:491–512CrossRefGoogle Scholar
  6. Jacobson ES (2000) Pathogenic roles for fungal melanins. Clin Microbiol Rev 13:708–717CrossRefGoogle Scholar
  7. Kim S, Ahn IP, Rho HS, Lee YH (2005) MHP1, a Magnaporthe grisea hydrophobin gene, is required for fungal development and plant colonization. Mol Microbiol 57:1224–1237CrossRefGoogle Scholar
  8. Langfelder K, Streibel M, Jahn B, Haase G, Brakhage AA (2003) Biosynthesis of fungal melanins and their importance for human pathogenic fungi. Fungal Genet Biol 38:143–158CrossRefGoogle Scholar
  9. Lee BN, Adams TH (1994) The Aspergillus nidulans fluG gene is required for production of an extracellular developmental signal and is related to prokaryotic glutamine synthetase I. Genes Dev 8:641–651CrossRefGoogle Scholar
  10. Li XY, Han XX, Liu ZQ, He C (2013) The function and properties of the transcriptional regulator COS1 in Magnaporthe oryzae. Fungal Biol 117:239–249CrossRefGoogle Scholar
  11. Liu KJ, Suresh A, Willard FS et al (2014) Rgs1 regulates multiple Gα subunits in Magnaporthe, pathogenesis, asexual growth and thigmotropism. Embo J 26(3):690–700CrossRefGoogle Scholar
  12. Livak KJ, Schmittgen TD (2001) Analysis of relative gene expression data using real-time quantitive PCR and the 2-∆∆C t method. Methods 25:402–408CrossRefGoogle Scholar
  13. Maciel JL, Ceresini PC, Castroagudin VL, Zala M, Kema GH, McDonald BA (2014) Population structure and pathotype diversity of the wheat blast pathogen Magnaporthe oryzae 2.5 years after its emergence in Brazil. Phytopathology 104:95–107CrossRefGoogle Scholar
  14. Matheis S, Yemelin A, Scheps D et al (2017) Functions of the Magnaporthe oryzae Flb3p and Flb4p transcription factors in the regulation of conidiation. Microbiol Res 196:106CrossRefGoogle Scholar
  15. Morris-Jones R, Gomez BL, Diez S, Uran M, Morris-Jones SD, Casadevall A, Nosanchuk JD, Hamilton AJ (2005) Synthesis of melanin pigment by Candida albicans in vitro and during infection. Infect Immun 73:6147–6150CrossRefGoogle Scholar
  16. Nalley L, Tisboe F, Durand-Morat A, Shew A, Thoma G (2016) Economic and environmental impact of rice blast pathogen (Magnaporthe oryzae) alleviation in the United States. PLoS One 11:e0167295CrossRefGoogle Scholar
  17. Ramanujam R, Yishi X, Liu H, Naqvi NI (2012) Structure-function analysis of Rgs1 in Magnaporthe oryzae: role of DEP domains in subcellular targeting. PLoS One 7:e41084CrossRefGoogle Scholar
  18. Silue D, Tharreau D, Talbot NJ, Clergeot PH, Notteghem JL, Lebrun MH (1998) Identification and characterization of apf1—in anon-pathogenic mutant of the rice blast fungus Magnaporthe grisea which is unable to differentiate appressoria. Physiol Mol Plant Pathol 53:239–251CrossRefGoogle Scholar
  19. Talbot NJ (2003) On the trail of a cereal killer: exploring the biology of Magnaporthe grisea. Annu Rev Microbiol 57:177–202CrossRefGoogle Scholar
  20. Wang ZY, Soanes DM, Kershaw MJ, Talbot NJ (2007) Functional analysis of lipid metabolism in Magnaporthe grisea reveals a role for peroxisomal fatty acid beta-oxidation during appressorium-mediated plant infection. Mol Plant Microbe Interact 20:475–491CrossRefGoogle Scholar
  21. Weijn A, Bastiaan-Net S, Wichers HJ, Mes JJ (2013) Melanin biosynthesis pathway in Agaricusbisporu smushrooms. Fungal Genet Biol 55:42–53CrossRefGoogle Scholar
  22. Wilson RA, Talbot NJ (2009) Under pressure; investigating the biology of plant infection by Magnaporthe oryzae. Nat Rev Microbiol 7:185–195CrossRefGoogle Scholar
  23. Zhang CQ, Zhu GN, Ma ZH et al (2010) Isolation, characterization and preliminary genetic analysis of laboratory tricyclazole-resistant mutants of the rice blast fungus, Magnaporthe grisea. J Phytopathol 154(7–8):392–397Google Scholar
  24. Zhou ZZ, Li G, Lin C, He C (2009) Conidiophore Stalk-less1 encodes a putative zinc-finger protein involved in the early stage of conidiation and mycelial infection in Magnaporthe oryzae. Mol Plant Microbe Interact 22:402–410CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • He Na
    • 1
  • An Bang
    • 1
  • Xie Qing-biao
    • 1
  • Yan Xia
    • 1
  • Feng Hui-min
    • 1
  • Luo Hong-li
    • 1
  • He Chao-zu
    • 1
    Email author
  1. 1.Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and ForestryHainan UniversityHaikouChina

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