Abstract
Background: Septoria tritici blotch (STB), caused by Zymoseptoria tritici (Z. tritici), is an important biotic threat to durum wheat in the entire Mediterranean Basin. Although most durum wheat cultivars are susceptible to Z. tritici, research in STB resistance in durum wheat has been limited.
Results: In our study, we have identified resistance to a wide array of Z. tritici isolates in the Tunisian durum wheat landrace accession 'Agili39'. Subsequently, a recombinant inbred population was developed and tested under greenhouse conditions at the seedling stage with eight Z. tritici isolates and for five years under field conditions with three Z. tritici isolates. Mapping of quantitative trait loci (QTL) resulted in the identification of two major QTL on chromosome 2B designated as Qstb2B_1 and Qstb2B_2. The Qstb2B_1 QTL was mapped at the seedling and the adult plant stage (highest LOD 33.9, explained variance 61.6%), conferring an effective resistance against five Z. tritici isolates. The Qstb2B_2 conferred adult plant resistance (highest LOD 32.9, explained variance 42%) and has been effective at the field trials against two Z. tritici isolates. The physical positions of the flanking markers linked to Qstb2B_1 and Qstb2B_2 indicate that these two QTL are 5 Mb apart. In addition, we identified two minor QTL on chromosomes 1A (Qstb1A) and chromosome 7A (Qstb7A) (highest LODs 4.6 and 4.0, and explained variances of 16% and 9%, respectively) that were specific to three and one Z. tritici isolates, respectively. All identified QTL were derived from the landrace accession Agili39 that represents a valuable source for STB resistance in durum wheat.
Conclusion: This study demonstrates that Z. tritici resistance in the 'Agili39' landrace accession is controlled by two minor and two major QTL acting in an additive mode. We also provide evidence that the broad efficacy of the resistance to STB in 'Agili 39' is due to a natural pyramiding of these QTL. A sustainable use of this Z. tritici resistance source and a positive selection of the linked markers to the identified QTL will greatly support effective breeding for Z. tritici resistance in durum wheat.
| Original language | English (US) |
|---|---|
| Journal | BMC genomics |
| Volume | 23 |
| Issue number | 1 |
| DOIs | |
| State | Published - May 17 2022 |
Bibliographical note
KAUST Repository Item: Exported on 2022-05-23Acknowledgements: We would like to thank Els Verstappen and all members of Bio-interaction and Plant health (Wageningen University and Research) for excellent technical support, Nicolas Letreux and Bertus Van der Laan (Unifarm, Wageningen University) for greenhouse assistance and maintenance. We, also would like to thank all members of the Genetics and Plant Breeding group at the National Institute of Agronomy, Tunisia , and staff members at the Regional Field Crops and Research Center—Beja (Tunisia) for field assistance, and CIMMYT staff members (Mexico) for genotyping support. We, finally, highly acknowledge Paul Keizer and Pieter Vereijken (Biometris, Wageningen University and Research) for providing statistical support.
The research was partly supported by the Japan International Cooperation Agency (JICA)–Japan Science and Technology Agency (JST)’s Science and Technology Research Partnership for Sustainable Development (SATREPS) under the project entitled “Valorization of Bio-resources in Semi-Arid and Arid Land for Regional Development”.
LA was financially supported by the Monsanto's Beachell-Borlaug International Scholars Program (3,340,030,501) and The ‘Bourse d’alternance’ from the Ministry of Higher Education and Scientific Research—Tunisia.
ASJC Scopus subject areas
- Genetics
- Biotechnology