scholarly journals SNP-based Genetic Structure of Tunisian Durum Wheat Landraces and Distribution of the Resistance to Septoria Tritici Blotch

2021 ◽  
Author(s):  
Maroua Ouaja ◽  
Bochra Bahri ◽  
Sahbi Ferjaoui ◽  
Maher Medini ◽  
Udupa . Sripa ◽  
...  
Keyword(s):  
Population Structure ◽  
Durum Wheat ◽  
Eastern Mediterranean ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Mediterranean Populations ◽  
Population Structure Analysis ◽  
Wheat Landraces ◽  
Durum Wheat Landraces

Abstract Background: Septoria tritici blotch (STB) has marked durum wheat production worldwide. This fungal disease is until today a challenge for farmers, researchers and breeders all united in the aim of reducing its damage and improving wheat resistance. Tunisian durum wheat landraces were reported to be valuable genetic resources for resistance to biotic and abiotic stresses and are therefore prominently deployed in breeding programs to develop new varieties adapted to fungal diseases as STB and to climate change constraints overall.Results: A total of 366 local durum wheat accessions were assessed for resistance to two virulent Tunisian isolates of Zymoseptoria tritici Tun06 and TM220 under field conditions. Population structure analysis of the durum wheat accessions, performed with 286 polymorphic SNPs (PIC >0.3) covering the entire genome, identified three genetic subpopulations (GS1, GS2 and GS3) with 22% of admixed genotypes. Interestingly, all of the resistant genotypes were among GS2 or admixed with GS2. Conclusions: This study revealed the population structure and the genetic distribution of the resistance to Z. tritici in the Tunisian durum wheat landraces. The grouping pattern of accessions appear to be associated, to some extent, with the geographical pattern of the landraces. We suggested that GS2 accessions were mostly introduced from eastern Mediterranean populations, unlike GS1 and GS3 that originated from the west. Resistant GS2 accessions belonged to landraces Taganrog, Sbei glabre, Richi, Mekki, Badri, Jneh Khotifa and Azizi. Furthermore, we suggested that admixture contributed to transmit STB resistance from GS2 resistant landraces to initially susceptible landraces such as Mahmoudi (GS1), but also resulted in the loss of resistance in the case of GS2 suscpetible Azizi and Jneh Khotifa accessions.

scholarly journals SNP-Based Genetic Structure of Tunisian Durum Wheat Landraces and Distribution of the Resistance to Septoria Tritici Blotch

2021 ◽  
Author(s):  
Maroua Ouaja ◽  
Bochra Bahri ◽  
Sahbi Ferjaoui ◽  
Maher Medini ◽  
Udupa M. Sri ◽  
...  
Keyword(s):  
Population Structure ◽  
Durum Wheat ◽  
Eastern Mediterranean ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Mediterranean Populations ◽  
Population Structure Analysis ◽  
Wheat Landraces ◽  
Durum Wheat Landraces

Abstract Background: Septoria tritici blotch (STB) has marked durum wheat production worldwide. This fungal disease is until today a challenge for farmers, researchers and breeders all united in the aim of reducing its damage and improving wheat resistance. Tunisian durum wheat landraces were reported to be valuable genetic resources for resistance to biotic and abiotic stresses and are therefore prominently deployed in breeding programs to develop new varieties adapted to fungal diseases as STB and to climate change constraints overall.Results: A total of 366 local durum wheat accessions were assessed for resistance to two virulent Tunisian isolates of Zymoseptoria tritici Tun06 and TM220 under field conditions. Population structure analysis of the durum wheat accessions, performed with 286 polymorphic SNPs (PIC >0.3) covering the entire genome, identified three genetic subpopulations (GS1, GS2 and GS3) with 22% of admixed genotypes. Interestingly, all of the resistant genotypes were among GS2 or admixed with GS2. Conclusions: This study revealed the population structure and the genetic distribution of the resistance to Z. tritici in the Tunisian durum wheat landraces. The grouping pattern of accessions appear to be associated, to some extent, with the geographical pattern of the landraces. We suggested that GS2 accessions were mostly introduced from eastern Mediterranean populations, unlike GS1 and GS3 that originated from the west. Resistant GS2 accessions belonged to landraces Taganrog, Sbei glabre, Richi, Mekki, Badri, Jneh Khotifa and Azizi. Furthermore, we suggested that admixture contributed to transmit STB resistance from GS2 resistant landraces to initially susceptible landraces such as Mahmoudi (GS1), but also resulted in the loss of resistance in the case of GS2 suscpetible Azizi and Jneh Khotifa accessions.

scholarly journals Genetic diversity of Ethiopian durum wheat landraces

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247016
Author(s):  
Kefyalew Negisho ◽  
Surafel Shibru ◽  
Klaus Pillen ◽  
Frank Ordon ◽  
Gwendolin Wehner
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Durum Wheat ◽  
Total Variation ◽  
Population Structure Analysis ◽  
Wheat Landraces ◽  
Wheat Lines ◽  
Durum Wheat Landraces

Genetic diversity and population structure assessment in crops is essential for marker trait association, marker assisted breeding and crop germplasm conservation. We analyzed a set of 285 durum wheat accessions comprising 215 Ethiopian durum wheat landraces, 10 released durum wheat varieties, 10 advanced durum wheat lines from Ethiopia, and 50 durum wheat lines from CIMMYT. We investigated the genetic diversity and population structure for the complete panel as well as for the 215 landraces, separately based on 11,919 SNP markers with known physical positions. The whole panel was clustered into two populations representing on the one hand mainly the landraces, and on the other hand mainly released, advanced and CIMMYT lines. Further population structure analysis of the landraces uncovered 4 subgroups emphasizing the high degree of genetic diversity within Ethiopian durum landraces. Population structure based AMOVA for both sets unveiled significant (P < 0.001) variation between populations and within populations. Total variation within population accessions (81%, 76%) was higher than total variation between populations (19%, 24%) for both sets. Population structure analysis based genetic differentiation (FST) and gene flow (Nm) for the whole set and the Ethiopian landraces were 0.19 and 0.24, 1.04, and 0.81, respectively indicating high genetic differentiation and limited gene flow. Diversity indices verify that the landrace panel was more diverse with (I = 0.7, He = 0.46, uHe = 0.46) than the advanced lines (I = 0.6, He = 0.42, uHe = 0.42). Similarly, differences within the landrace clusters were observed. In summary a high genetic diversity within Ethiopian durum wheat landraces was detected, which may be a target for national and international wheat improvement programs to exploit valuable traits for biotic and abiotic stresses.

scholarly journals Behavior of Spanish durum wheat genotypes against Zymoseptoria tritici: resistance and susceptibility

2021 ◽  
Vol 19 (3) ◽  
pp. e1002-e1002
Author(s):  
Rafael Porras ◽  
Keyword(s):  
Durum Wheat ◽  
Agronomic Traits ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Sources Of Resistance ◽  
Breeding Lines ◽  
Wheat Genotypes ◽  
Commercial Cultivars ◽  
Growth Chambers

Aim of study: Septoria tritici blotch (STB), caused by the fungus Zymoseptoria tritici, is one of the most important wheat diseases worldwide, affecting both bread and durum wheat. The lack of knowledge about the interaction of durum wheat with Z. tritici, together with limited resources of resistant durum wheat material, have both led to a rising threat for durum wheat cultivation, particularly in the Mediterranean Basin. In Spain, STB has increased its incidence in the last few years, leading to higher costs of fungicide applications to control the disease. Therefore, identification of new sources of resistance through wheat breeding stands out as an efficient method of facing STB. Area of study: The experimental study was conducted in growth chambers at the IFAPA facilities in Córdoba (Spain). Material and methods: The percentage of necrotic leaf area, the disease severity, and the pycnidium development through image analysis were evaluated from 48 durum wheat Spanish accessions (breeding lines and commercial cultivars) in growth chambers against an isolate of Z. tritici from Córdoba. Main results: Two breeding lines and six commercial cultivars showed resistant responses by limiting STB development through the leaf or its reproduction ability, while the other 40 accessions presented a susceptible response. Research highlights: Provided these resources of resistance in Spanish durum wheat genotypes, future breeding programs could be developed, incorporating both agronomic traits and resistance to STB.

scholarly journals Tramesan Elicits Durum Wheat Defence Against the Septoria Leaf Blotch Complex

2020 ◽  
Author(s):  
VALERIA Scala ◽  
Chiara Pietricola ◽  
valentina farina ◽  
marzia beccaccioli ◽  
slaven zjalic ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Field Experiments ◽  
Animal Health ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Animal Cells ◽  
Zymoseptoria Tritici ◽  
Septoria Leaf Blotch ◽  
Leaf Blotch ◽  
Wheat Field

The Septoria Leaf Blotch Complex (SLBC), caused by the two ascomycetes Zymoseptoria tritici and Parastagonospora nodorum, can reduce global yearly yield of wheat by up to 50%. In the last decade in Italy, SLBC incidence has increased; notably, durum wheat has proven to be more susceptible than common wheat. Field fungicide treatment can efficiently control these pathogens, but it leads to the emergence of resistant strains and adversely affects human and animal health, and the environment. Our previous studies indicated that active compounds produced by Trametes versicolor can restrict the growth of mycotoxigenic fungi and the biosynthesis of their secondary metabolites (e.g. mycotoxins). Specifically, we identified Tramesan: a 23 KDa -heteropolysaccharide secreted by T. versicolor that acts as a pro-antioxidant molecule in animal cells, fungi, and plants. Foliar-spraying of Tramesan (3.3 &micro;M) in SLBC-susceptible varieties of durum significantly diminished symptoms of Stagonospora Nodorum Blotch (SNB) and Septoria Tritici Blotch (STB) by 75% and 65%, respectively. Tests were conducted under controlled conditions as well as in field. We show that Tramesan elicits wheat defence against SNB and STB augmenting the synthesis of defence-related hormones, notably JA and SA, that in turn switch on the expression of markers of defence (PR1, PR4 inter alia). In field experiments, yield of durum wheat plants treated with Tramesan was similar to that of untreated ones. The results suggest the use of Tramesan for protecting durum wheat against SLBC.

Identification of valuable sources of resistance to Zymoseptoria tritici in the Tunisian durum wheat landraces

2020 ◽  
Vol 156 (2) ◽  
pp. 647-661 ◽  
Author(s):  
Maroua Ouaja ◽  
Lamia Aouini ◽  
Bochra Bahri ◽  
Sahbi Ferjaoui ◽  
Maher Medini ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Zymoseptoria Tritici ◽  
Sources Of Resistance ◽  
Wheat Landraces ◽  
Durum Wheat Landraces

scholarly journals Life story of Tunisian durum wheat landraces revealed by their genetic and phenotypic diversity

2020 ◽  
Author(s):  
Safa Ben Krima ◽  
Amine Slim ◽  
Sandrine Gélisse ◽  
Hajer Kouki ◽  
Isabelle Nadaud ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Life Story ◽  
Triticum Turgidum ◽  
Phenotypic Diversity ◽  
Quantitative Resistance ◽  
Farming Systems ◽  
Septoria Tritici ◽  
Genetic Groups ◽  
Wheat Landraces ◽  
Durum Wheat Landraces

AbstractDurum wheat (Triticum turgidum L. subsp. durum) landraces represent a prominent genetic resource for Mediterranean farming systems and breeding programs. Fourteen landraces sampled in Tunisia were genotyped with 9 microsatellite markers and characterized with 15 morphological descriptors, including resistance to the fungal disease Septoria tritici blotch (STB). The genetic diversity, nearly was as important within landraces populations (45%) than between populations (54%). It was structured in seven genetic groups and was only partly explained by the variety name or the locality of origin. Populations were also greatly diversified phenotypically (Shannon-Weaver H’=0.54) with traits related to spike and awn colours being the most diversified. Resistance to STB was either qualitative in two populations or with varying degrees of quantitative resistance in the others. A Pst-Fst comparison indicate a local adaptation of the populations. Overall, the genetic structure of Tunisian durum wheat landraces revealed a complex selection trajectory and seed exchanges between farmers.

scholarly journals Tramesan Elicits Durum Wheat Defense against the Septoria Disease Complex

Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 608 ◽  
Author(s):  
Valeria Scala ◽  
Chiara Pietricola ◽  
Valentina Farina ◽  
Marzia Beccaccioli ◽  
Slaven Zjalic ◽  
...  
Keyword(s):  
Plant Defense ◽  
Durum Wheat ◽  
Field Experiments ◽  
Disease Incidence ◽  
Animal Health ◽  
Foliar Spray ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Controlled Conditions

The Septoria Leaf Blotch Complex (SLBC), caused by the two ascomycetes Zymoseptoria tritici and Parastagonospora nodorum, can reduce wheat global yearly yield by up to 50%. In the last decade, SLBC incidence has increased in Italy; notably, durum wheat has proven to be more susceptible than common wheat. Field fungicide treatment can efficiently control these pathogens, but it leads to the emergence of resistant strains and adversely affects human and animal health and the environment. Our previous studies indicated that active compounds produced by Trametes versicolor can restrict the growth of mycotoxigenic fungi and the biosynthesis of their secondary metabolites (e.g., mycotoxins). Specifically, we identified Tramesan: a 23 kDa α-heteropolysaccharide secreted by T. versicolor that acts as a pro-antioxidant molecule in animal cells, fungi, and plants. Foliar-spray of Tramesan (3.3 μM) on SLBC-susceptible durum wheat cultivars, before inoculation of causal agents of Stagonospora Nodorum Blotch (SNB) and Septoria Tritici Blotch (STB), significantly decreased disease incidence both in controlled conditions (SNB: −99%, STB: −75%) and field assays (SNB: −25%, STB: −30%). We conducted these tests were conducted under controlled conditions as well as in field. We showed that Tramesan increased the levels of jasmonic acid (JA), a plant defense-related hormone. Tramesan also increased the early expression (24 hours after inoculation—hai) of plant defense genes such as PR4 for SNB infected plants, and RBOH, PR1, and PR9 for STB infected plants. These results suggest that Tramesan protects wheat by eliciting plant defenses, since it has no direct fungicidal activity. In field experiments, the yield of durum wheat plants treated with Tramesan was similar to that of healthy untreated plots. These results encourage the use of Tramesan to protect durum wheat against SLBC.

scholarly journals Unlocking the Patterns of the Tunisian Durum Wheat Landraces Genetic Structure Based on Phenotypic Characterization in Relation to Farmer’s Vernacular Name

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 634
Author(s):  
Cyrine Robbana ◽  
Zakaria Kehel ◽  
Karim Ammar ◽  
Carlos Guzmán ◽  
M’Barek Ben Naceur ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Durum Wheat ◽  
Smallholder Farmers ◽  
Phenotypic Variability ◽  
Phenotypic Characterization ◽  
Ecological Niches ◽  
Dry Conditions ◽  
New Gene ◽  
Wheat Landraces ◽  
Durum Wheat Landraces

During the 1970s, Tunisian durum wheat landraces were replaced progressively by modern cultivars. These landraces are nowadays maintained by smallholder farmers in some ecological niches and are threatened gradually by extinction resulting in the narrowing of the genetic diversity. This study aims to investigate patterns of phenotypic variability using twelve quantitative traits in a panel of 189 durum wheat landraces and seven checks, based on farmer’s population name attribution and genetic structure. Our results showed high phenotypic variability among and within landraces and checks for ten out of twelve studied traits. The principal components analysis showed similar grouping using farmers name attribution and genetic structure using K = 6. These results confirmed the identification of a new gene pool in the oases of Tunisia, represented by the sub-population Jenah Zarzoura and the robustness and high relationships between phenotypic and genome-wide genetic structure using DArTseq method. These findings will enhance the conservation efforts of these landraces and their use in breeding efforts at national and international levels to adapt to dry conditions.

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