Dataset Information

Exploring genetic diversity of wild and related tetraploid wheat species Triticum turgidum and Triticum timopheevii.

ABSTRACT:

Introduction

The domestication bottleneck has reduced genetic diversity inwheat, necessitating the use of wild relatives in breeding programs. Wild tetraploid wheat are widely used in the breeding programs but with morphological characters, it is difficult to distinguish these, resulting in misclassification/mislabeling or duplication of accessions in the Gene bank.

Objectives

The study aims to exploreGenotyping by sequencing (GBS) to characterize wild and domesticated tetraploid wheat accessions to generate a core set of accessions to be used in the breeding program.

Methods

TASSEL-GBS pipeline was used for SNP discovery, fastStructure was used to determine the population structure and PowerCore was used to generate a core sets. Nucleotide diversity matrices of Nie's and F-statistics (F_ST) index were used to determine the center of genetic diversity.

Results

We found 65 % and 47 % duplicated accessions in Triticum timopheevii and T. turgidum respectively. Genome-wide nucleotide diversity and F_ST scan uncovered a lower intra and higher inter-species differentiation. Distinct F_ST regions were identified in genomic regions belonging to domestication genes: non-brittle rachis (Btr1) and vernalization (VRN-1).Our results suggest that Israel, Jordan, Syria, and Lebanonas the hub of genetic diversity of wild emmer;Turkey, and Georgia for T. durum; and Iraq, Azerbaijan, and Armenia for theT. timopheevii. Identified core set accessions preserved more than 93 % of the available genetic diversity. Genome wide association study (GWAS) indicated the potential chromosomal segment for resistance to leaf rust in T. timopheevii.

Conclusion

The present study explored the potential of GBS technology in data reduction while maintaining the significant genetic diversity of the species. Wild germplasm showed more differentiation than domesticated accessions, indicating the availability of sufficient diversity for crop improvement. With reduced complexity, the core set preserves the genetic diversity of the gene bank collections and will aid in a more robust characterization of wild germplasm.

SUBMITTER: Yadav IS

PROVIDER: S-EPMC10248793 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Exploring genetic diversity of wild and related tetraploid wheat species Triticum turgidum and Triticum timopheevii.

Yadav Inderjit S IS Singh Narinder N Wu Shuangye S Raupp Jon J Wilson Duane L DL Rawat Nidhi N Gill Bikram S BS Poland Jesse J Tiwari Vijay K VK

Journal of advanced research 20220907

<h4>Introduction</h4>The domestication bottleneck has reduced genetic diversity inwheat, necessitating the use of wild relatives in breeding programs. Wild tetraploid wheat are widely used in the breeding programs but with morphological characters, it is difficult to distinguish these, resulting in misclassification/mislabeling or duplication of accessions in the Gene bank.<h4>Objectives</h4>The study aims to exploreGenotyping by sequencing (GBS) to characterize wild and domesticated tetraploid ...[more]

PMID: 36084813

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Project description:BackgroundThe ability to engineer cereal crops by gene transfer technology is a powerful and informative tool for discovering and studying functions of genes controlling environmental adaptability and nutritional value. Tetraploid wheat species such as emmer wheat and Timopheevi wheat are the oldest cereal crops cultivated in various world areas long before the Christian era. Nowadays, these hulled wheat species are gaining new interest as donors for gene pools responsible for the improved grain yield and quality, tolerance for abiotic and biotic stress, resistance to pests and disease. The establishing of efficient gene transfer techniques for emmer and Timopheevi wheat may help in creation of modern polyploid wheat varieties.ResultsIn the present study, we describe a robust protocol for the production of fertile transgenic plants of cultivated emmer wheat (Russian cv. 'Runo') using a biolistic delivery of a plasmid encoding the gene of green fluorescent protein (GFP) and an herbicide resistance gene (BAR). Both the origin of target tissues (mature or immature embryos) and the type of morphogenic calli (white or translucent) influenced the efficiency of stable transgenic plant production in emmer wheat. The bombardment of nodular white compact calluses is a major factor allowed to achieve the highest transformation efficiency of emmer wheat (on average, 12.9%) confirmed by fluorescence, PCR, and Southern blot. In the absence of donor plants for isolation of immature embryos, mature embryo-derived calluses could be used as alternative tissues for recovering transgenic emmer plants with a frequency of 2.1%. The biolistic procedure based on the bombardment of immature embryo-derived calluses was also successful for the generation of transgenic Triticum timopheevii wheat plants (transformation efficiency of 0.5%). Most of the primary events transmitted the transgene expression to the sexual progeny.ConclusionThe procedures described here can be further used to study the functional biology and contribute to the agronomic improvement of wheat. We also recommend involving in such research the Russian emmer wheat cv. 'Runo', which demonstrates a high capacity for biolistic-mediated transformation, exceeding the previously reported values for different genotypes of polyploid wheat.

Project description:Levels of genetic diversity and population genetic structure of a collection of 230 accessions of seven tetraploid Triticum turgidum L. subspecies were investigated using six morphological, nine seed storage protein loci, 26 SSRs and 970 DArT markers. The genetic diversity of the morphological traits and seed storage proteins was always lower in the durum wheat compared to the wild and domesticated emmer. Using Bayesian clustering (K = 2), both of the sets of molecular markers distinguished the durum wheat cultivars from the other tetraploid subspecies, and two distinct subgroups were detected within the durum wheat subspecies, which is in agreement with their origin and year of release. The genetic diversity of morphological traits and seed storage proteins was always lower in the improved durum cultivars registered after 1990, than in the intermediate and older ones. This marked effect on diversity was not observed for molecular markers, where there was only a weak reduction. At K >2, the SSR markers showed a greater degree of resolution than for DArT, with their identification of a greater number of groups within each subspecies. Analysis of DArT marker differentiation between the wheat subspecies indicated outlier loci that are potentially linked to genes controlling some important agronomic traits. Among the 211 loci identified under selection, 109 markers were recently mapped, and some of these markers were clustered into specific regions on chromosome arms 2BL, 3BS and 4AL, where several genes/quantitative trait loci (QTLs) are involved in the domestication of tetraploid wheats, such as the tenacious glumes (Tg) and brittle rachis (Br) characteristics. On the basis of these results, it can be assumed that the population structure of the tetraploid wheat collection partially reflects the evolutionary history of Triticum turgidum L. subspecies and the genetic potential of landraces and wild accessions for the detection of unexplored alleles.

Project description:BackgroundTunisia is considered a secondary center of diversification of durum wheat and has a large number of abandoned old local landraces. An accurate investigation and characterization of the morphological and genetic features of these landraces would allow their rehabilitation and utilization in wheat breeding programs. Here, we investigated a diverse collection of 304 local accessions of durum wheat collected from five regions and three climate stages of central and southern Tunisia.ResultsDurum wheat accessions were morphologically characterized using 12 spike- and grain-related traits. A mean Shannon-Weaver index (H') of 0.80 was obtained, indicating high level of polymorphism among accessions. Based on these traits, 11 local landraces including Mahmoudi, Azizi, Jneh Khotifa, Mekki, Biskri, Taganrog, Biada, Badri, Richi, Roussia and Souri were identified. Spike length (H' = 0.98), spike shape (H' = 0.86), grain size (H' = 0.94), grain shape (H' = 0.87) and grain color (H' = 0.86) were the most polymorphic morphological traits. The genetic diversity of these accessions was assessed using 10 simple sequence repeat (SSR) markers, with a polymorphic information content (PIC) of 0.69. Levels of genetic diversity were generally high (I = 0.62; He = 0.35). In addition, population structure analysis revealed 11 genetic groups, which were significantly correlated with the morphological characterization. Analysis of molecular variance (AMOVA) showed high genetic variation within regions (81%) and within genetic groups (41%), reflecting a considerable amount of admixture between landraces. The moderate (19%) and high (59%) levels of genetic variation detected among regions and among genetic groups, respectively, highlighted the selection practices of farmers. Furthermore, Mahmoudi accessions showed significant variation in spike density between central Tunisia (compact spikes) and southern Tunisia (loose spikes with open glume), may indicate an adaptation to high temperature in the south.ConclusionOverall, this study demonstrates the genetic richness of local durum wheat germplasm for better in situ and ex situ conservation and for the subsequent use of these accessions in wheat breeding programs.

Project description:Key messageFunctional redundancy and subfunctionalization of β-hydroxylases in tetraploid wheat tissues open up opportunities for manipulation of carotenoid metabolism for trait improvement. The genetic diversity provided by subgenome homoeologs in allopolyploid wheat can be leveraged for developing improved wheat varieties with modified chemical traits, including profiles of carotenoids, which play critical roles in photosynthesis, photoprotection, and growth regulation. Carotenoid profiles are greatly influenced by hydroxylation catalyzed by β-hydroxylases (HYDs). To genetically dissect the contribution of HYDs to carotenoid metabolism and wheat growth and yield, we isolated loss-of-function mutants of the two homoeologs of HYD1 (HYD-A1 and HYD-B1) and HYD2 (HYD-A2 and HYD-B2) from the sequenced ethyl methanesulfonate mutant population of the tetraploid wheat cultivar Kronos, and generated various mutant combinations. Although functional redundancy between HYD1 and HYD2 paralogs was observed in leaves, HYD1 homoeologs contributed more than HYD2 homoeologs to carotenoid β-ring hydroxylation in this tissue. By contrast, the HYD2 homoeologs functioned toward production of lutein, the major carotenoid in mature grains, whereas HYD1 homoeologs had a limited role. These results collectively suggested subfunctionalization of HYD genes and homoeologs in different tissues of tetraploid wheat. Despite reduced photoprotective responses observed in the triple hyd-A1 hyd-B1 hyd-A2 and the quadruple hyd-A1 hyd-B1 hyd-A2 hyd-B2 combinatorial mutants, comprehensive plant phenotyping analysis revealed that all mutants analyzed were comparable to the control for growth, yield, and fertility, except for a slight delay in anthesis and senescence as well as accelerated germination in the quadruple mutant. Overall, this research takes steps toward untangling the functions of HYDs in wheat and has implications for improving performance and consumer traits of this economically important global crop.

Dataset Information

Exploring genetic diversity of wild and related tetraploid wheat species Triticum turgidum and Triticum timopheevii.

Introduction

Objectives

Methods

Results

Conclusion

Publications

Exploring genetic diversity of wild and related tetraploid wheat species Triticum turgidum and Triticum timopheevii.

Similar Datasets

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