scholarly journals Polymorphism of Sdr genes regulating seed dormancy in Triticum persicum Vav. and Triticum aethiopicum Jakubz.

2020 ◽  
Vol 23 (8) ◽  
pp. 964-971
Author(s):  
M. S. Bazhenov ◽  
E. D. Guseva ◽  
V. S. Rubets
Keyword(s):  
Common Wheat ◽  
Seed Dormancy ◽  
Association Studies ◽  
Physiological State ◽  
Tetraploid Wheat ◽  
Preharvest Sprouting ◽  
Local Varieties ◽  
Promising Area ◽  
Triticum Aethiopicum ◽  
Main Component

Preharvest sprouting of wheat grain, sporadically observed in many regions of cultivation of this crop, leads to deterioration of its food and sowing qualities. Seed dormancy is considered to be the main component of resistance to preharvest sprouting. This physiological state of seeds is regulated by many genes, and it depends heavily on environmental conditions. One of the regulators of seed dormancy in cereals is the Sdr4 gene (Seed dormancy 4), which was first studied in rice. In common wheat, the homologues of this gene (TaSdr-A1 and TaSdr-B1) are also involved in the regulation of seed dormancy. The search for valuable alleles in local varieties and endemic forms is a promising area of research aimed at increasing the resistance of crops to adverse environmental factors. In this study, Sdr genes were sequenced in several accessions of two tetraploid wheat species with limited cultivation areas: Persian wheat (Triticum persicum Vav.) and Ethiopian wheat (Triticum aethiopicum Jakubz.). As a result, the same Sdr-A1 and Sdr-B1 variants that had been found in common wheat were detected in these species. The Persian wheat accessions possessed only the Sdr-A1a allele, while Ethiopian ones, only Sdr-A1b. The analysis of F2 hybrids obtained from crossing these tetraploid species showed that the Sdr-A1b allele was associated with a lower germination index of grains than Sdr-A1a. This result was inconsistent with earlier association studies. Previously unknown polymorphisms were found in the promoter of the Sdr-B1 gene in the studied accessions. A deletion of 16 nucleotides was detected in the 3’-terminal region of the TraesCS2B02G215200 gene, located on the complementary DNA chain close to the 3’-end of the Sdr-B1 gene. Possible effects of the detected polymorphisms on the expression of Sdr genes are discussed.

scholarly journals Genetically Divergent Types of the Wheat Leaf Fungus Puccinia triticina in Ethiopia, a Center of Tetraploid Wheat Diversity

2016 ◽  
Vol 106 (4) ◽  
pp. 380-385 ◽  
Author(s):  
J. A. Kolmer ◽  
M. A. Acevedo
Keyword(s):  
Leaf Rust ◽  
Common Wheat ◽  
Hexaploid Wheat ◽  
Rust Fungus ◽  
Tetraploid Wheat ◽  
Low Frequency ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Virulence Phenotype ◽  
Wheat Leaf

Collections of Puccinia triticina, the wheat leaf rust fungus, were obtained from tetraploid and hexaploid wheat in the central highlands of Ethiopia, and a smaller number from Kenya, from 2011 to 2013, in order to determine the genetic diversity of this wheat pathogen in a center of host diversity. Single-uredinial isolates were derived and tested for virulence phenotype to 20 lines of Thatcher wheat that differ for single leaf rust resistance genes and for molecular genotypes with 10 simple sequence repeat (SSR) primers. Nine virulence phenotypes were described among the 193 isolates tested for virulence. Phenotype BBBQJ, found only in Ethiopia, was predominantly collected from tetraploid wheat. Phenotype EEEEE, also found only in Ethiopia, was exclusively collected from tetraploid wheat and was avirulent to the susceptible hexaploid wheat ‘Thatcher’. Phenotypes MBDSS and MCDSS, found in both Ethiopia and Kenya, were predominantly collected from common wheat. Phenotypes CCMSS, CCPSS, and CBMSS were found in Ethiopia from common wheat at low frequency. Phenotypes TCBSS and TCBSQ were found on durum wheat and common wheat in Kenya. Four groups of distinct SSR genotypes were described among the 48 isolates genotyped. Isolates with phenotypes BBBQJ and EEEEE were in two distinct SSR groups, and isolates with phenotypes MBDSS and MCDSS were in a third group. Isolates with CCMSS, CCPSS, CBMSS, TCBSS, and TCBSQ phenotypes were in a fourth SSR genotype group. The diverse host environment of Ethiopia has selected and maintained a genetically divergent population of P. triticina.

Microglia and its genetics in Alzheimer's Disease

2021 ◽  
Vol 18 ◽  
Author(s):  
Xinyan Liang ◽  
Haijian Wu ◽  
Mark Colt ◽  
Xinying Guo ◽  
Brock Pluimer ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Immune Cell ◽  
Morphological Changes ◽  
Association Studies ◽  
Unmet Need ◽  
Genome Wide Association Studies ◽  
Protective Effects ◽  
Risk Genes ◽  
Main Component

: Alzheimer’s Disease (AD) is the most prevalent form of dementia across the world. While its discovery and pathological manifestations are centered on protein aggregations of amyloid-beta (Aβ) and hyperphosphorylated tau protein, neuroinflammation has emerged in the last decade as a main component of the disease in both pathogenesis and progression. As the main innate immune cell type in central nervous system (CNS), microglia play a very important role in regulating neuroinflammation, which occurs commonly in neurodegenerative conditions including AD. Under inflammatory response, microglia undergo morphological changes and status transition from homeostatic to activated forms. Different microglia subtypes displaying distinct genetic profiles have been identified in AD, and these signatures often link to AD risk genes identified from the genome-wide association studies (GWAS), such as APOE and TREM2. Furthermore, many of AD risk genes are highly enriched in microglia and specifically influence the functions of microglia in pathogenesis, e.g. releasing inflammatory cytokines and clearing Aβ. Therefore, building up a landscape of these risk genes in microglia, based on current preclinical studies and in the context of their pathogenic or protective effects, would largely help us to understand the complexed etiology of AD and provide new insight for the unmet need of effective treatment.

scholarly journals Interactions of the barley SD1 and SD2 seed dormancy loci influence preharvest sprouting, seed dormancy, and malting quality

Crop Science ◽  
2021 ◽  
Author(s):  
Daniel W. Sweeney ◽  
Travis E. Rooney ◽  
Jason G. Walling ◽  
Mark E. Sorrells
Keyword(s):  
Seed Dormancy ◽  
Preharvest Sprouting ◽  
Malting Quality

Evaluation and selection of bread wheat (Triticum aestivum L.) for preharvest sprouting tolerance

1995 ◽  
Vol 46 (3) ◽  
pp. 463 ◽  
Author(s):  
RM Trethowan
Keyword(s):  
Bread Wheat ◽  
Seed Dormancy ◽  
Triticum Aestivum L ◽  
Preharvest Sprouting ◽  
First Year ◽  
Falling Number ◽  
Selection For ◽  
Visual Measurements ◽  
Selection Of ◽  
Rain Simulator

This paper examines the success of selection for preharvest sprouting tolerance in white-grained bread wheat using a standard wetting treatment, germination of hand-threshed seed and falling number measurements. The rain simulator was usefull in shifting the population mean of field grown material towards higher levels of tolerance in successive years; however, large genotype x year interactions in material sown under rain protection did not allow accurate assessment of individual genotypes. The most accurate assessments were achieved using falling number measurements (h2 = 80.7%) and hand-threshed seed germinations (h2 = 38.4%), where no genotype x year interactions were recorded. Seed dormancy (determined from hand threshed grain) correlated significantly with change in falling number following 3 days' treatment in the rain simulator ( r = -0-56**). Visual measurements scored in the rain simulator, however, did not correlate significantly with seed dormancy in the first year (r = 0.20) but correlated strongly in the second (r = 0.73***). In comparisons of the same test between years, falling number (without rain treatment) and seed dormancy were significantly correlated (r = 0.68* and 0.90***, respectively), whilst visual scores of sprouting showed no association (r = -0.03).

scholarly journals Fusarium Head Blight in Durum Wheat: Recent Status, Breeding Directions, and Future Research Prospects

2019 ◽  
Vol 109 (10) ◽  
pp. 1664-1675 ◽  
Author(s):  
Jemanesh K. Haile ◽  
Amidou N’Diaye ◽  
Sean Walkowiak ◽  
Kirby T. Nilsen ◽  
John M. Clarke ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Fusarium Head Blight ◽  
Seed Quality ◽  
Association Studies ◽  
Tetraploid Wheat ◽  
The United States ◽  
Genome Wide Association Studies ◽  
Head Blight ◽  
Food And Feed ◽  
Fhb Resistance

Fusarium head blight (FHB) is a major fungal disease affecting wheat production worldwide. Since the early 1990s, FHB, caused primarily by Fusarium graminearum, has become one of the most significant diseases faced by wheat producers in Canada and the United States. The increasing FHB problem is likely due to the increased adoption of conservation tillage practices, expansion of maize production, use of susceptible wheat varieties in rotation, and climate variability. Durum wheat (Triticum turgidum sp. durum) is notorious for its extreme susceptibility to FHB and breeding for resistance is complicated because sources of FHB resistance are rare in the primary gene pool of tetraploid wheat. Losses due to this disease include yield, test weight, seed quality, food and feed quality, and when severe, market access. More importantly, it is the contamination with mycotoxins, such as deoxynivalenol, in Fusarium-infected durum kernels that causes the most serious economic as well as food and feed safety concerns. Several studies and thorough reviews have been published on germplasm development and breeding for FHB resistance and the genetics and genomics of FHB resistance in bread or common wheat (T. aestivum); however, similar reviews have not been conducted in durum wheat. Thus, the aim of this review is to summarize and discuss the recent research efforts to mitigate FHB in durum wheat, including quantitative trait locus mapping, genome-wide association studies, genomic prediction, mutagenesis and characterization of genes and pathways involved in FHB resistance. It also highlights future directions, FHB-resistant germplasm, and the potential role of morphological traits to enhance FHB resistance in durum wheat.

SEED DORMANCY | Preharvest Sprouting

2003 ◽  
pp. 1333-1339
Author(s):  
R.L. Benech-Arnold ◽  
R.A. Sánchez
Keyword(s):  
Seed Dormancy ◽  
Preharvest Sprouting

Tetraploid wheat species Triticum timopheevii and Triticum militinae in common wheat improvement

2002 ◽  
Vol 50 (4) ◽  
pp. 463-477 ◽  
Author(s):  
K Järve ◽  
I. Jakobson ◽  
T. Enno
Keyword(s):  
Disease Resistance ◽  
Common Wheat ◽  
Tetraploid Wheat ◽  
Introgressive Hybridization ◽  
Fungal Diseases ◽  
Triticum Timopheevii ◽  
Wheat Species ◽  
Major Genes ◽  
Wheat Improvement ◽  
Unknown Species

Timopheevii wheats are discussed as donors for improving the disease resistance of common wheat. Attention is paid to the comparison of the morphological and chromosomal characteristics of Triticum timopheevii and T. militinae, their crossability with T. aestivum and their response to fungal diseases. The possible origin of T. militinae from an introgressive hybridization between T. timopheevii and an unknown species is discussed. Major genes for resistance to various fungal diseases, transferred to common wheat from T. timopheevii, are listed.

scholarly journals Nanopore RNA Sequencing Revealed Long Non-Coding and LTR Retrotransposon-Related RNAs Expressed at Early Stages of Triticale SEED Development

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1794
Author(s):  
Ilya Kirov ◽  
Maxim Dudnikov ◽  
Pavel Merkulov ◽  
Andrey Shingaliev ◽  
Murad Omarov ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Seed Development ◽  
Association Studies ◽  
Expression Patterns ◽  
Genome Wide Association Studies ◽  
Ltr Retrotransposon ◽  
Ltr Retrotransposons ◽  
Junk Dna ◽  
Early Stages ◽  
Main Component

The intergenic space of plant genomes encodes many functionally important yet unexplored RNAs. The genomic loci encoding these RNAs are often considered “junk”, DNA as they are frequently associated with repeat-rich regions of the genome. The latter makes the annotations of these loci and the assembly of the corresponding transcripts using short RNAseq reads particularly challenging. Here, using long-read Nanopore direct RNA sequencing, we aimed to identify these “junk” RNA molecules, including long non-coding RNAs (lncRNAs) and transposon-derived transcripts expressed during early stages (10 days post anthesis) of seed development of triticale (AABBRR, 2n = 6x = 42), an interspecific hybrid between wheat and rye. Altogether, we found 796 lncRNAs and 20 LTR retrotransposon-related transcripts (RTE-RNAs) expressed at this stage, with most of them being previously unannotated and located in the intergenic as well as intronic regions. Sequence analysis of the lncRNAs provide evidence for the frequent exonization of Class I (retrotransposons) and class II (DNA transposons) transposon sequences and suggest direct influence of “junk” DNA on the structure and origin of lncRNAs. We show that the expression patterns of lncRNAs and RTE-related transcripts have high stage specificity. In turn, almost half of the lncRNAs located in Genomes A and B have the highest expression levels at 10–30 days post anthesis in wheat. Detailed analysis of the protein-coding potential of the RTE-RNAs showed that 75% of them carry open reading frames (ORFs) for a diverse set of GAG proteins, the main component of virus-like particles of LTR retrotransposons. We further experimentally demonstrated that some RTE-RNAs originate from autonomous LTR retrotransposons with ongoing transposition activity during early stages of triticale seed development. Overall, our results provide a framework for further exploration of the newly discovered lncRNAs and RTE-RNAs in functional and genome-wide association studies in triticale and wheat. Our study also demonstrates that Nanopore direct RNA sequencing is an indispensable tool for the elucidation of lncRNA and retrotransposon transcripts.

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