Mitochondrial DNA-based genetic diversity and population structure of Zymoseptoria tritici in Tunisia
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A total of 108 isolates of the wheat pathogen Zymoseptoria tritici were collected from four distinct locations of Tunisia and characterized for three mitochondrial DNA sequences to provide insight into the genetic diversity and population structure of the fungus in this country. The number of different alleles averaged over all loci within locations ranged from 3.33 to 5.67, with an average of 4.42 per location. Multilocus analysis identified 27 (25 %) distinct haplotypes among the 108 assessed isolates, revealing a high mtDNA-based clonality within the population. Three of the highlighted haplotypes occurred in all locations and nine of them covered at least two locations. Significant levels of genetic diversity were found for the whole population and within each of the sampled locations, as indicated by the Nei’s gene diversity (0.52), unbiased gene diversity (0.58) and allele richness (4.43) indices. Further analyzes using Bayesian and non-Bayesian statistical models, as well as AMOVA, showed a lack of mtDNA-based genetic structure (GST = 0.06), hence supporting previous reports on Z. tritici in Tunisia performed using nuclear-DNA markers. A high level of gene flow (Nm = 8.27) corroborates the lack of structure and suggests regular cycles of sexual reproduction, leading to allelic pool homogenization via wind-born ascospores in the Tunisian population of Z. tritici.
KeywordsZymoseptoria tritici Mitochondrial DNA Genetic diversity Population structure SSCP
This research was supported by financial supports from the University of El-Manar (Tunis, Tunisia) and the Higher Institute of Agriculture (Lille, France).
- Anon, A. (1996). The evaluation of forensic DNA evidence. Washington: National Academy Press. 272 pages.Google Scholar
- Boukef, S., Yahyaoui, A., & Rezgui, S. (2013). Geographical distribution of a specific mitochondrial haplotype of Zymoseptoria tritici. Phytopathologia Mediterranea, 52, 466–471.Google Scholar
- Goodwin, S. B., Ben M’Barek, S., Dhillon, B., Wittenberg, A. H. J., Crane, C. F., Hane, J. K., et al. (2011). Finished genome of the fungal wheat pathogen Mycosphaerella graminicola reveals dispensome structure, chromosome plasticity, and stealth pathogenesis. PLoS Genetics, 7(6), e1002070. doi: 10.1371/journal.pgen.1002070.CrossRefPubMedPubMedCentralGoogle Scholar
- Goudet, J. (2001). FSTAT, a program to estimate and test gene diversities and fixation indices (version 2.9.3) (http://www2.unil.ch/popgen/softwares/fstat.htm).
- Kabbage, M., Leslie, J. F., Zeller, K. A., Hulbert, S. H., & Bockus, W. W. (2008). Genetic diversity of Mycosphaerella graminicola, the causal agent of Septoria tritici blotch, in Kansas winter wheat. Journal of Agricultural Food and Environmental Sciences, 2, 1–9.Google Scholar
- Kudla, J., Albertazzi, F. J., Blazevic, D., Hermann, M., & Bock, R. (2002). Loss of the mitochondrial cox2 intron 1 in a family of monocotyledonous plants and utilization of mitochondrial intron sequences for the construction of a nuclear intron. Molecular Genetics and Genomics, 267, 223–230.CrossRefPubMedGoogle Scholar
- Liu, Y. C., Cortesi, P., Double, M. L., MacDonald, W. L., & Milgroom, M. G. (1996). Diversity and multilocus genetic structure in populations of Cryphonectria parasitica. Phytopathology, 86, 1344–1351.Google Scholar
- McDonald, B. A., Zhan, J., Yarden, O., Hogan, K., Garton, J., & Pettway, R. E. (1999). The population genetics of Mycosphaerella graminicola and Phaeosphaeria nodorum. In J. A. Lucas, P. Bowyer, & H. M. Anderson (Eds.), Septoria on cereals: A study of pathosystems (pp. 44–69). Wallingford: CAB International.Google Scholar
- Naouari, M., Siah, A., Elgazzah, M., Reignault, P., & Halama, P. (2013). Tunisian population of the wheat pathogen Mycosphaerella graminicola is still fully sensitive to strobilurin fungicides. Journal of Agricultural Science and Technology, 3, 955–959.Google Scholar
- Orita, M., Iwahana, H., Kanazawa, H., Hayashi, K., & Sekiya, T. (1989). Detection of polymorphisms of human DNA by gel electrophoresis as single-strand conformation polymorphisms. Proceedings of the National Academy of Sciences of the United States of America, 86, 2766–2770.CrossRefPubMedPubMedCentralGoogle Scholar
- Siah, A., Tisserant, B., El Chartouni, L., Duyme, F., Deweer, C., Fichter, C., Sanssené, J., Durand, R., Reignault, P., & Halama, P. (2010). Mating type idiomorphs from a French population of the wheat pathogen Mycosphaerella graminicola: widespread equal distribution and low but distinct levels of molecular polymorphism. Fungal Biology, 114, 980–990.CrossRefGoogle Scholar
- Torriani, S. F. F., Goodwin, S. B., Kema, G. H. J., Pandilinan, J. L., & McDonald, B. A. (2008). Intraspecific comparison and annotation of two complete mitochondrial genome sequences from the plant pathogenic fungus Mycosphaerella graminicola. Fungal Genetics and Biology, 45, 628–637.CrossRefPubMedGoogle Scholar
- Yeh, F. C., Yang, R., & Boyle, T. (2000). Popgene 1.32. The user-friendly software for population genetic analysis. Molecular Biology and Biotechnology Center, Univ Alberta, and CIFOR, Canada (https://www.ualberta.ca/~fyeh/index.html).
- Youssar, L., Grüning, B. A., Günther, S., & Hüttel, W. (2013). Characterization and phylogenetic analysis of the mitochondrial genome of Glarea lozoyensis indicates high diversity within the order Helotiales. PLoS ONE, 8(9), e74792. doi: 10.1371/journal.pone.0074792.CrossRefPubMedPubMedCentralGoogle Scholar
- Zhan, J., Pettway, R. E., & McDonald, B. A. (2003). The global genetic structure of the wheat pathogen Mycosphaerella graminicola is characterized by high nuclear diversity, low mitochondrial diversity, regular recombination, and gene flow. Fungal Genetics and Biology, 38, 286–297.CrossRefPubMedGoogle Scholar