A serine/threonine-protein phosphatase PP2A catalytic subunit is essential for asexual development and plant infection in Magnaporthe oryzae
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Protein phosphatase 2A is a subgroup of widely conserved serine/threonine phosphatases and plays diverse roles in transcription, translation, differentiation, cell cycle, and signal transduction in many organisms. However, its roles in biotrophic and hemi-biotrophic phytopathogenic fungi remain to be investigated. In this study, we isolated an insertional mutant of the rice blast fungus Magnaporthe oryzae that was defective in vegetative hyphal growth. In the mutant, the T-DNA fragment was found to be inserted in the promoter region of a putative serine/threonine protein phosphatase 2A catalytic subunit (PP2Ac) gene MoPPG1. Deletion of MoPPG1 leads to severe defects in vegetative hyphal growth and conidiation. Conidia of the ∆Moppg1 null mutants were misshaped, and most of them were two-celled. The deletion mutants of MoPPG1 did not penetrate into host plant cells and failed to cause any disease lesions on rice leaves. Interestingly, significant reduction was found in the ∆Moppg1 null mutants in expression levels of several Rho GTPase family genes including MgCDC42, MgRHO3, and MgRAC1, which were important for pathogenesis of M. oryzae. Taken together, our results indicated that PP2Ac plays vital roles in asexual development and plant infection by regulating Rho GTPases in the rice blast fungus and perhaps other plant pathogenic fungi.
KeywordsConidiation Pathogenicity Rice blast fungus Serine/threonine protein phosphatase Vegetative hyphal growth
We thank Dr. Wensheng Zhao and Yan Zhang at China Agricultural University for helpful discussions. This work was supported by a grant from the National Fundamental Basic Research program (2012CB114002) to Y. -L. Peng of the Ministry of Sciences and Technology, China.
Conflict of interest
We declared that no conflict of interest exists.
- Dean RA, Talbot NJ, Ebbole DJ, Farman ML, Mitchell TK, Orbach MJ, Thon M, Kulkarni R, Xu JR, Pan HQ, Read ND, Lee YH, Carbone I, Brown D, Oh YY, Donofrio N, Jeong JS, Soanes DM, Djonovic S, Kolomiets E, Rehmeyer C, Li WX, Hardling M, Kim S, Lebrun MH, Bohnert H, Coughlan S, Butler J, Calvo S, Ma LJ, Nicol R, Purcell S, Nusbaum C, Galagan JE, Birren BW (2005) The genome sequence of the rice blast fungus Magnaporthe oryzae. Nature 434:980–986PubMedCrossRefGoogle Scholar
- Jeon J, Park SY, Chi MH, Choi J, Park J, Rho HS, Kim S, Goh J, Yoo S, Choi J, Park JY, Yi M, Yang S, Kwon MJ, Han SS, Kim BR, Khang CH, Park B, Lim SE, Jung K, Kong S, Karunakaran M, Oh HS, Kim H, Kim S, Park J, Kang S, Choi WB, Kang S, Lee YH (2007) Genome-wide functional analysis of pathogenicity genes in the rice blast fungus. Nat Genet 39:561–565PubMedCrossRefGoogle Scholar
- Li G, Zhou X, Xu JR (2012) Genetic control of infection-related development in Magnaporthe oryzae. Curr Opin Microbiol. doi: 10.1016/j.mib.2012.09.004
- Sambrook J, Russell D (2001) Molecular cloning: a laboratory manual. Cold Spring Harbor Laboratory Press, New YorkGoogle Scholar
- Zheng W, Chen J, Zheng S, Liu L, Liu S, Lu G, Zhou J, Wang Z (2006) Rho proteins and the expression module of their encoding genes in Magnaporthe grisea. Acta Phytopathol Sinica 36:328–336Google Scholar