Equal Distribution of Mating Type Alleles and the Presence of Strobilurin Resistance in Algerian Zymoseptoria tritici Field Populations

Abstract

Zymoseptoria tritici, the causal agent of septoria tritici blotch, is an important wheat pathogen responsible for high yield losses worldwide. The assessment of the distribution of both mating type idiomorphs was studied in several wheat-growing areas in North Algeria. Both mating types occurred at all spatial scales tested and showed an equal frequency distribution at the country level, with 53% for Mat1-1 and 47% for Mat1-2. At finer scales, co-occurrence of both mating types was found in 38% of leaves analyzed and 44% of the studied lesions. Additionally, efficacy reduction of strobilurin applications prompted us to study strobilurin resistance conferred by the G143A substitution in the mitochondrial cytochrome b gene, which was found for the first time in six strains. The results suggest that the Algerian Z. tritici population undergoes frequent sexual reproduction mirrored by co-occurrence of both mating types, which likely will rapidly increase the fraction of strobilurin-resistant isolates in the Algerian population, as has been shown in all other regions where strobilurin resistance surfaced.

Deciphering resistance to Zymoseptoria tritici in the Tunisian durum wheat landrace accession ‘Agili39’

“…Recent research increased the general understanding of the Z. tritici epidemiology in the Maghreb. Hamada [ 17 ] reported the occurrence of the teleomorph of the fungus in Tunisia, despite the arid conditions in the region, and Neddaf et al [ 18 ] determined an equal distribution of both mating types in Algeria, indicating regular sexual reproduction, which likely contributes to the vast genetic diversity in this region. Similar results have recently been reported in Tunisia on durum wheat [ 19 ].…”

“…Similar results have recently been reported in Tunisia on durum wheat [ 19 ]. The use of fungicides has been more slowly adopted by durum wheat growers as compared to bread wheat producers in Europe, and the first occurrence of strobilurin resistance have been reported in Tunisia and Algeria [ 18 , 20 ].…”

First report of the Zymoseptoria tritici teleomorph stage causing septoria leaf blotch of wheat in Algeria

“…Mycosphaerella graminicola ) is considered to be one of the major diseases affecting both durum and bread wheat in Algeria. Algerian Z. tritici populations undergo frequent sexual reproduction mirrored by cooccurrence of both mating types (Allioui et al , 2014; Meamiche Neddaf et al , 2017). Pseudothecia have been obtained under controlled conditions (Ayad et al , 2014), however the natural occurrence of the teleomorph stage has never been reported in the country.…”