GENETIC VARIABILITY AT THE b-MATING TYPE LOCUS IN Ustilago maydis IN EGYPT AND ITS MOLECULAR IDENTIFICATION | ||||
| Assiut Journal of Agricultural Sciences | ||||
| Article 11, Volume 37, Issue 3, October 2006, Page 153-171 PDF (880.77 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ajas.2006.274634 | ||||
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| Authors | ||||
| F. M. Saleh; M. M. El-Defrawy; R. F. Abdou; A F. Mohammed | ||||
| Genetics department, Faculty of Agriculture, Assiut University, Assiut, Egypt. | ||||
| Abstract | ||||
| This present investigation was carried out to study the variation at the b mating type in the basidiomycete fungus Ustilago maydis, the causal agent of corn smut disease. Different isolates were collected from: Assiut, Sohag, Menia, Sharqiya, Daqahlia,Giza and Kalubia governorates in Egypt. Eight different b mating types were identified among the samples with approximately equal frequencies. The b1 , b3 and b8 alleles were the most frequent, whereas the alleles b4 and b6 were the least frequent. The allele b4 was absent in Sohag samples whereas the allele b6 was absent in Assiut, Menia and Lower Egypt samples. The gene diversity Gst (population differentiation) for b mating types within and between subpopulation were calculated. The total diversity over all populations was 85.86 and the average gene diversity within populations was 82.79 and the gene diversity among population was 3.07 indicating that the majority of gene diversity was occurring in small spatial scale. Low population differentiation was indicated by the low GST values among populations, suggesting corresponding high degree of gene flow in these population. Ten U. maydis samples collected from four geographic regions (Assiut, Sohag, Menia and Lower Egypt) and belonging to different b mating types had been selected for RAPD analysis. Such analysis generated 40 discrete DNA bands ranging from 150-2500 bp in size. Twenty seven of which were polymorphic (67.50), with an average of 8 bands per primer. One putative a2 mating type specific band was generated with primer OPO-12 of 2400 bp in size. Results indicated that no relationship between the RAPD profile and geographic sites where isolates were collected from. | ||||
| Keywords | ||||
| Ustilago maydis; genetic variability; b mating type locus | ||||
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