International Symposium on Cereal Leaf Blights 2019 | University College Dublin, Ireland | 22-24 May 2019

High genetic diversity among Zymoseptoria tritici isolates from bread wheat in Northern Tunisia


Rim Bel Hadj Chedli*
National Agronomic Institute of Tunisia (INAT), 43 Avenue Charles Nicolle, 1002 Tunis, Tunisia.

Lamia Aouini
Department of Agronomy, Purdue University, 915 West State Street, West Lafayette, IN 47907

Sarrah Ben M'Barek
Regional Field Crop Research Center of Beja (CRRGC) BP 350, 9000 Beja, Tunisia.
CRP Wheat Septoria Phenotyping Platform, Tunisia

Bochra Amina Bahri
National Agronomic Institute of Tunisia (INAT), 43 Avenue Charles Nicolle, 1002 Tunis, Tunisia.

Els Verstappen
WageningenUniversity and Research Center, Wageningen, The Netherlands

Gerrit H J Kema
WageningenUniversity and Research Center, Wageningen, The Netherlands

Salah Rezgui
National Agronomic Institute of Tunisia (INAT), 43 Avenue Charles Nicolle, 1002 Tunis, Tunisia.

Amor Yahyaoui
Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT), km 45 Carretera México-Veracruz El Batan, Texcoco
CRP Wheat Septoria Phenotyping Platform, Tunisia


Poster Presentation
Evolution and Population Biology

Atrium, UCD O'Brien centre for Science
Poster 6

View this abstract online by visting isclb2019.com/see/ABS93193

Septoria tritici blotch (SLB) is the most important foliar disease of durum wheat in Tunisia, hence previous genetic diversity analyses of the local Zymoseptoria tritici population mainly concentrated on isolates derived from Triticum durum. In this study, Z. tritici populations from bread wheat were investigated. A total of 184 single-pycnidial fungal isolates were recovered from naturally infected bread wheat leaves sampled in three main Tunisian growing areas (El Haouaria, Bizerte and Beja). The collection was assessed for mating type idiomorphs and genetic structure using 12 microsatellite markers at region and field scales. The results revealed high genetic diversity in the collected population. El Haouaria displayed the highest level of polymorphism (100%) and the highest Shannon diversity index (0.84).  Such high diversity in El Haouaria is likely due to an active sexual reproduction of the pathogen, which is supported by the equal frequencies of the two mating types in that region. The study also revealed the absence of genetic variation in the Oued Zargua population in Beja region, suggesting that clonal pycnidiospores are the major source of primary infections. This study is the first population analysis of Z. tritici isolates from bread wheat in Tunisia and provides important insights into the genetic structure and epidemiology of STB that would be useful for an effective disease management.