The structure of genetic diversity of Septoria tritici blotch within and among five major wheat growing regions in Morocco were assessed by AFLP （Amplified Fragment Length Polymorphism technique）. A total of 596 ban...The structure of genetic diversity of Septoria tritici blotch within and among five major wheat growing regions in Morocco were assessed by AFLP （Amplified Fragment Length Polymorphism technique）. A total of 596 bands were obtained from four primers. The mean percentage of polymorphic loci over all populations was 46.56%. Nord Tangerois region had the highest loci （80.03%）, followed by Gharb region （73.66%）. The mean population diversity using Shannon information index was （I = 0.293, SE = 0.0112） and the mean gene flow was 9.12. Genetic diversity value ranged from 0.66 to 0.93 with an average of 0.78. All five populations had high levels of gene diversity. High levels of gene flow and low genetic differentiation was observed among regions （PhiPT = 0.0.057, P = 0.017）. AMOVA （Analysis of Molecular Variance） showed that there was a small but statistically significant level of genetic differentiation among populations from the five bread wheat regions. However, most of the total genetic variation （94%） occurred within wheat regions while 6% was due to genetic differentiation between these regions. Results provide evidence that sexual recombination occurs frequently in the Mycosphaerella graminicola populations sampled and that most populations are genetically differentiated over the major bread wheat growing areas in Morocco.展开更多
Mycosphaerella graminieola （anamorph： Zymoseptoria tritici） is the causal agent of Septoria tritici blotch, the most frequently occurring disease on wheat crops worldwide. A set of 163 monoconidial isolates of this...Mycosphaerella graminieola （anamorph： Zymoseptoria tritici） is the causal agent of Septoria tritici blotch, the most frequently occurring disease on wheat crops worldwide. A set of 163 monoconidial isolates of this fungus were sampled in 2012 from five geographical locations of Tunisia （Bizerte, B6ja, Kef, Jendouba and Siliana） in order to examine the status of strobilurin resistance of M. graminicola in this country. The resistance was assessed by using PCR-based mismatch mutation assay that determined the cytochrome b substitution G143A responsible for strobilurin resistance. All isolates were found sensitive since they possessed the wild-type allele G143 conferring sensitivity. This study confirms previous reports on the fungus in Tunisia and reveals that the Tunisian population of M. graminicola remains fully sensitive to strobilurin fungicides. An appropriate management of strobilurin applications in Tunisia is thereby recommended to prevent local development and widespread of resistance, as in Europe, where pathogen populations are fully resistant to strobilurins today.展开更多
文摘The structure of genetic diversity of Septoria tritici blotch within and among five major wheat growing regions in Morocco were assessed by AFLP （Amplified Fragment Length Polymorphism technique）. A total of 596 bands were obtained from four primers. The mean percentage of polymorphic loci over all populations was 46.56%. Nord Tangerois region had the highest loci （80.03%）, followed by Gharb region （73.66%）. The mean population diversity using Shannon information index was （I = 0.293, SE = 0.0112） and the mean gene flow was 9.12. Genetic diversity value ranged from 0.66 to 0.93 with an average of 0.78. All five populations had high levels of gene diversity. High levels of gene flow and low genetic differentiation was observed among regions （PhiPT = 0.0.057, P = 0.017）. AMOVA （Analysis of Molecular Variance） showed that there was a small but statistically significant level of genetic differentiation among populations from the five bread wheat regions. However, most of the total genetic variation （94%） occurred within wheat regions while 6% was due to genetic differentiation between these regions. Results provide evidence that sexual recombination occurs frequently in the Mycosphaerella graminicola populations sampled and that most populations are genetically differentiated over the major bread wheat growing areas in Morocco.
文摘Mycosphaerella graminieola （anamorph： Zymoseptoria tritici） is the causal agent of Septoria tritici blotch, the most frequently occurring disease on wheat crops worldwide. A set of 163 monoconidial isolates of this fungus were sampled in 2012 from five geographical locations of Tunisia （Bizerte, B6ja, Kef, Jendouba and Siliana） in order to examine the status of strobilurin resistance of M. graminicola in this country. The resistance was assessed by using PCR-based mismatch mutation assay that determined the cytochrome b substitution G143A responsible for strobilurin resistance. All isolates were found sensitive since they possessed the wild-type allele G143 conferring sensitivity. This study confirms previous reports on the fungus in Tunisia and reveals that the Tunisian population of M. graminicola remains fully sensitive to strobilurin fungicides. An appropriate management of strobilurin applications in Tunisia is thereby recommended to prevent local development and widespread of resistance, as in Europe, where pathogen populations are fully resistant to strobilurins today.
