By: H. Benslimane*, L. Lamari, A.Benbelkacem, R. Sayoud, and Z.Bouznad *Corresponding author: benslimh@yahoo.fr

1. Races distribution of Pyrenophora tritici-repentis in Algeria and consequences of new virulence
type identification in some basis of P. tritici-repentis / Wheat pathosystem
BENSLIMANE1 H., L. LAMARI2, A. BENBELKACEM3, R. SAYOUD4 and Z. BOUZNAD5
1Université M’hamed Bougra, Boumerdès, Faculté des Science, Département de Biologie, Laboratoire de Biologie Moléculaire, 16 Rue de l’indépendance, Boumerdès, Algéria.
2 University of Manitoba, Department of Plant Sciences, Winnipeg, Manitoba, Canada, RT3 2N2.
3 Institut National de la Recherche Agronomique d’Algérie, Unité de Recherche de Constantine, Station ITGC, Elkhroub, Algéria.
4SYNGENTA, 5 chemin des citernes Skikda, Algérie. 5 Ecole Nationale Supérieure d’Agronomie, Département de Botanique, , El-Harrach, Alger, Algéria
Abstract
Tan spot, caused by Pyrenophora tritici-repentis, is a foliar disease of wheat, responsible for high economic losses in several wheat growing areas in the
world. There are eight known races of P. tritici-repentis based on ability to induce necrosis and/or chlorosis on a set of differential cultivars. 55 isolates
originating from diverse wheat growing regions in Algeria were studied to determine which races are present and to identify new races. Races 1, 4, 5, 6, 7
and 8 were found and a new virulence pattern was identified. Isolates with this pattern induced necrosis in durum wheat but failed to induce any disease
in the common wheat genotypes in the differential set.
Materiel and Method
Fungal isolates: Plant material: The differential set was made up of Durum and bread wheat
55 isolates of P. tritici-repentis were used in this study., obtained from several
infected wheat fields (Durum and bread wheat) in different cereal growing areas in Bread wheat A) Glenlea B) 6B-662 C) 6B-365 D) Salamouni
Durum wheat E) 4B-1149 F) Coulter G) 4B-160
Algeria. 3 isolates (Asc1, 86-124, Alg-3-24) corresponding, respectively, to 3 known
races (1, 2, and 5) were used as controls (Benslimane and al., 2011). Inoculum production and Inoculation: Protocols of Lamari and Bernier (1989)
Results and Discussion
Isolates evaluated were grouped into six races New virulence Type (Race 9 ??)
Race 4 Race 5 Race 6 Race 7 Race 8 Race 1
5 isolates from durum wheat showed a new virulence pattern, they were able to attach only durum wheat genotypes. Bread wheat genotypes harbored in their genomes the three gens
(Tsn1, Tsc2, Tsc1) responsible for sensitivity to the three knows toxins (PtrToxA, PtrToxB and PtrToxC). This suggests that isolates with the new virulence pattern are not able to
produce the three HTS.s. However, these isolates could possess a novel toxin(s)( Benslimane et al., 2011)
Distribution of Pyrenophora tritici-repentis races in Algeria Percentage of each race founded in Algeria
The majority of isolates recovered
from the samples represented races
1 and 7, while races 4, 5, 6, and 8
were more rare.
Four races (1, 4, 7, and 8) were
described in Algeria for the first
time.
Consequences in Pyrenophora tritici-repentis/ Wheat Pathosystem Conclusion
The presence of this putative new race, involves a significant impact on some bases of This study reveals that the tan spot fungus is highly variable in Algeria and a new race
wheat / P. tritici-repentis pathosystem. It is recognized that races 2, 3 and 5 are has been identified. This new race should produce a new toxin(s) and should be a
considered as a basic races because they are able to produce a single toxin. While others new basic race. These results showed that the genotypes used in the Algerian fields are
races 1, 6, 7 and 8 are considered as combined from basic races (Strelkov and Lamari, more sensitive to race 7 and race 1. These investigations should be of direct benefit to
2003). The discovery of a new race able to produce a single toxin completely different wheat breeding programs aimed at incorporating resistance to this pathogen. Plant
from those known, imply the existence of a new basic race. Consequence , the model breeders require knowledge of what races are present in the pathogen population in
proposed by Strelkov and Lamari (2003) establishing the relationship between different
order to determine which gene (s) should be present in resistant cultivars. The
races is permissible only when the host / pathogen interaction is considered for bread
development of wheat varieties that resist to this disease under current and future
wheat. The introduction of durum wheat in the host differential set makes the
climates in Algeria is therefore, of great importance.
hypothesis invalid (Benslimane, 2012).
Literature sited
1. Lamari L. and C.C. Bernier, 1989. Evaluation of wheat lines and cultivars to tan spot [Pyrenophora tritici-repentis] based on lesion type. Canadian Journal of Plant Pathology 11, 49–56.
2. Benslimane H. 2012. Etude de la tache bronzée du blé en Algérie: Identification des races de l’agent causal Pyrenophora tritici-repentis (Died.) Drechs et diversité génétique. PhD. Thesis,
ENSA, Algiers,157p.
3. Benslimane H., L. Lamari, A. Benbelkacem, R. Sayoud and Z. Bouznad, 2011. Distribution of races of Pyrenophora tritici-repentis in Algeria and identification of a new virulence type.
Phytopathologia Mediterranea, 50: 203−211.
4. Strelkov S.E. and Lamari L .2003. Host- parasite interactions in tan spot [Pyrenophora tritici- repentis] of wheat. Canadian Journal of Plant Pathology 25:339-349.