scholarly journals Aegilops sharonensis: Origin, genetics, diversity, and potential for wheat improvement

Botany ◽  
2009 ◽  
Vol 87 (8) ◽  
pp. 740-756 ◽  
Author(s):  
Pablo D. Olivera ◽  
Brian J. Steffenson
Keyword(s):  
Agricultural Intensification ◽  
Phenotypic Diversity ◽  
Grass Species ◽  
Wheat Diseases ◽  
B Genome ◽  
Diverse Species ◽  
Wheat Improvement ◽  
Aegilops Sharonensis ◽  
Variable Environments ◽  
A Genome

Aegilops sharonensis  Eig (Sharon goatgrass; section Sitopsis) is an annual diploid grass species growing endemically in the coastal plains of Israel and southern Lebanon. It is a wild relative of wheat, with a genome closely related to the B genome of cultivated bread wheat. With the most limited distribution of any species in the genus Aegilops, Ae. sharonensis is rapidly losing its habitats, owing to the combined effects of modern agricultural intensification and expansion of urban and industrial areas. Aegilops sharonensis is known to be a rich source of genes providing resistance to important wheat diseases and abiotic stresses, but it has not been widely exploited. The presence of gametocidal genes that control preferential transmission of chromosome 4Ssh increases the difficulty of introgressing genes from Ae. sharonensis into wheat. However, successful introgression of the genes for resistance to leaf rust, stripe rust, and powdery mildew has been achieved. Studies on genetic and phenotypic diversity indicated that Ae. sharonensis is a highly diverse species, comparable with others that have a wider geographic distribution and more variable environments. Targeting the regions and sites with the highest diversity in Ae. sharonensis will facilitate the capture of the greatest variability and also the identification of novel and diverse genes for wheat improvement.

Biochemical data bearing on the origin of the B genome in the polyploid wheats

Genome ◽  
1990 ◽  
Vol 33 (3) ◽  
pp. 360-368 ◽  
Author(s):  
K. Kerby ◽  
J. Kuspira ◽  
B. L. Jones ◽  
G. L. Lookhart
Keyword(s):  
Amino Acid ◽  
B Chromosome ◽  
Amino Acid Sequences ◽  
Chromosome 1 ◽  
Aegilops Speltoides ◽  
B Genome ◽  
Aegilops Longissima ◽  
Aegilops Sharonensis ◽  
A Genome ◽  
Genome Donors

For many years each of the species Aegilops bicornis, Aegilops longissima, Aegilops searsii, Aegilops sharonensis, Aegilops speltoides, and Triticum urartu has been implicated as the donor of the B genome in the polyploid wheats. Biochemical and cytological data have revealed that T. urartu possesses a genome similar to that of T. monococcum, and therefore it may be the source of the A genome in T. turgidum and T. aestivum. This revelation therefore excludes T. urartu from the list of putative B-genome donors. To determine which of the remaining species is the source of the B chromosome set, the amino acid sequences of their purothionins were compared with that of the α1 purothionin coded for by the Pur-1B gene on chromosome 1 in the B genome of T. turgidum and T. aestivum. The residue sequences of this protein from Ae. bicornis, Ae. longissima, Ae. searsii, Ae. sharonensis, and Ae. speltoides differed by 1, 6, 1, 1, and 2 amino acid substitutions, respectively, from the α1 protein. These results suggest that either Ae. bicornis, Ae. searsii, or Ae. sharonensis was the most likely donor of the B genome. If the B genome in the polyploid wheats is monophyletic in origin, the collective findings of this and other investigations indicate that Ae. searsii is the most likely donor. The possibility that the B genome in the polyploid wheats could have a polyphyletic origin is also discussed.Key words: polyploid wheats, putative B-genome donors, purothionins, monophyletic, polyphyletic.

scholarly journals Host genomic influence on bacterial composition in the switchgrass rhizosphere

2021 ◽  
Author(s):  
Jeremy Sutherland ◽  
Terrence Bell ◽  
Ryan V. Trexler ◽  
John E. Carlson ◽  
Jesse R. Lasky
Keyword(s):  
Genetic Variation ◽  
Life History ◽  
Genome Wide Association Study ◽  
Phenotypic Diversity ◽  
Alpha Diversity ◽  
Grass Species ◽  
Genotypic Differences ◽  
Life History Variation ◽  
Bacterial Composition ◽  
A Genome

AbstractHost genetic variation can shape the diversity and composition of associated microbiomes, which may reciprocally influence host traits and performance. While the genetic basis of phenotypic diversity of plant populations in nature has been studied, comparatively little research has investigated the genetics of host effects on their associated microbiomes. Switchgrass (Panicum virgatum) is a highly outcrossing, perennial, grass species with substantial locally adaptive diversity across its native North American range. Here, we compared 383 switchgrass accessions in a common garden to determine the host genotypic influence on rhizosphere bacterial composition. We hypothesized that the composition and diversity of rhizosphere bacterial assemblages would differentiate due to genotypic differences between hosts (potentially due to root phenotypes and associated life history variation). We observed higher alpha diversity of bacteria associated with upland ecotypes and tetraploids, compared to lowland ecotypes and octoploids, respectively. Alpha diversity correlated negatively with flowering time and plant height, indicating that bacterial composition varies along switchgrass life history axes. Narrow-sense heritability (h2) of the relative abundance of twenty-one core bacterial families was observed. Overall compositional differences among tetraploids, due to genetic variation, supports wide-spread genotypic influence on the rhizosphere microbiome. Lastly, a genome-wide association study identified 1,861 single-nucleotide polymorphisms associated with 110 families and genes containing them related to potential regulatory functions. Our findings suggest that switchgrass genomic and life-history variation influences bacterial composition in the rhizosphere, potentially due to host adaptation to local environments.

scholarly journals A Microsatellite Map of Wheat

Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 2007-2023 ◽  
Author(s):  
Marion S Röder ◽  
Victor Korzun ◽  
Katja Wendehake ◽  
Jens Plaschke ◽  
Marie-Hélène Tixier ◽  
...  
Keyword(s):  
Bread Wheat ◽  
Reference Population ◽  
Triticum Aestivum L ◽  
Wheat Genome ◽  
D Genome ◽  
B Genome ◽  
Microsatellite Map ◽  
A Genome ◽  
Polymorphic Microsatellite ◽  
Primer Sets

Abstract Hexaploid bread wheat (Triticum aestivum L. em. Thell) is one of the world's most important crop plants and displays a very low level of intraspecific polymorphism. We report the development of highly polymorphic microsatellite markers using procedures optimized for the large wheat genome. The isolation of microsatellite-containing clones from hypomethylated regions of the wheat genome increased the proportion of useful markers almost twofold. The majority (80%) of primer sets developed are genome-specific and detect only a single locus in one of the three genomes of bread wheat (A, B, or D). Only 20% of the markers detect more than one locus. A total of 279 loci amplified by 230 primer sets were placed onto a genetic framework map composed of RFLPs previously mapped in the reference population of the International Triticeae Mapping Initiative (ITMI) Opata 85 × W7984. Sixty-five microsatellites were mapped at a LOD >2.5, and 214 microsatellites were assigned to the most likely intervals. Ninety-three loci were mapped to the A genome, 115 to the B genome, and 71 to the D genome. The markers are randomly distributed along the linkage map, with clustering in several centromeric regions.

scholarly journals Three founding ancestral genomes involved in the origin of sugarcane

2021 ◽  
Author(s):  
Nicolas Pompidor ◽  
Carine Charron ◽  
Catherine Hervouet ◽  
Stéphanie Bocs ◽  
Gaëtan Droc ◽  
...  
Keyword(s):  
Evolutionary Model ◽  
Saccharum Officinarum ◽  
Modern Cultivar ◽  
Ploidy Levels ◽  
Saccharum Spp ◽  
Bac Clones ◽  
B Genome ◽  
A Genome ◽  
Genomic Regions ◽  
Complex Genome

Abstract Background and Aims Modern sugarcane cultivars (Saccharum spp.) are high polyploids, aneuploids (2n = ~12x = ~120) derived from interspecific hybridizations between the domesticated sweet species Saccharum officinarum and the wild species S. spontaneum. Methods To analyse the architecture and origin of such a complex genome, we analysed the sequences of all 12 hom(oe)ologous haplotypes (BAC clones) from two distinct genomic regions of a typical modern cultivar, as well as the corresponding sequence in Miscanthus sinense and Sorghum bicolor, and monitored their distribution among representatives of the Saccharum genus. Key Results The diversity observed among haplotypes suggested the existence of three founding genomes (A, B, C) in modern cultivars, which diverged between 0.8 and 1.3 Mya. Two genomes (A, B) were contributed by S. officinarum; these were also found in its wild presumed ancestor S. robustum, and one genome (C) was contributed by S. spontaneum. These results suggest that S. officinarum and S. robustum are derived from interspecific hybridization between two unknown ancestors (A and B genomes). The A genome contributed most haplotypes (nine or ten) while the B and C genomes contributed one or two haplotypes in the regions analysed of this typical modern cultivar. Interspecific hybridizations likely involved accessions or gametes with distinct ploidy levels and/or were followed by a series of backcrosses with the A genome. The three founding genomes were found in all S. barberi, S. sinense and modern cultivars analysed. None of the analysed accessions contained only the A genome or the B genome, suggesting that representatives of these founding genomes remain to be discovered. Conclusions This evolutionary model, which combines interspecificity and high polyploidy, can explain the variable chromosome pairing affinity observed in Saccharum. It represents a major revision of the understanding of Saccharum diversity.

scholarly journals Candidate genes and SNPs associated with stomatal conductance under drought stress in Vitis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Massimiliano Trenti ◽  
Silvia Lorenzi ◽  
Pier Luigi Bianchedi ◽  
Daniele Grossi ◽  
Osvaldo Failla ◽  
...  
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Candidate Genes ◽  
Water Deficit ◽  
Genetic Basis ◽  
Phenotypic Diversity ◽  
Snp Array ◽  
A Genome ◽  
Raffinose Synthase ◽  
Response To Water

Abstract Background Understanding the complexity of the vine plant’s response to water deficit represents a major challenge for sustainable winegrowing. Regulation of water use requires a coordinated action between scions and rootstocks on which cultivars are generally grafted to cope with phylloxera infestations. In this regard, a genome-wide association study (GWAS) approach was applied on an ‘ad hoc’ association mapping panel including different Vitis species, in order to dissect the genetic basis of transpiration-related traits and to identify genomic regions of grape rootstocks associated with drought tolerance mechanisms. The panel was genotyped with the GrapeReSeq Illumina 20 K SNP array and SSR markers, and infrared thermography was applied to estimate stomatal conductance values during progressive water deficit. Results In the association panel the level of genetic diversity was substantially lower for SNPs loci (0.32) than for SSR (0.87). GWAS detected 24 significant marker-trait associations along the various stages of drought-stress experiment and 13 candidate genes with a feasible role in drought response were identified. Gene expression analysis proved that three of these genes (VIT_13s0019g03040, VIT_17s0000g08960, VIT_18s0001g15390) were actually induced by drought stress. Genetic variation of VIT_17s0000g08960 coding for a raffinose synthase was further investigated by resequencing the gene of 85 individuals since a SNP located in the region (chr17_10,497,222_C_T) was significantly associated with stomatal conductance. Conclusions Our results represent a step forward towards the dissection of genetic basis that modulate the response to water deprivation in grape rootstocks. The knowledge derived from this study may be useful to exploit genotypic and phenotypic diversity in practical applications and to assist further investigations.

Putative diploid ancestors of 80-chromosome Glycine tabacina

Genome ◽  
1992 ◽  
Vol 35 (1) ◽  
pp. 140-146 ◽  
Author(s):  
R. J. Singh ◽  
K. P. Kollipara ◽  
F. Ahmad ◽  
T. Hymowitz
Keyword(s):  
Adventitious Roots ◽  
Chromosome Doubling ◽  
Colchicine Treatment ◽  
Meiotic Pairing ◽  
B Genome ◽  
Specific Hybridization ◽  
A Genome ◽  
Genome Homology ◽  
Glycine Tabacina ◽  
Natural Mutation

The objective of this study was to discover the diploid progenitors of 80-chromosome Glycine tabacina with adventitious roots (WAR) and no adventitious roots (NAR). Three synthetic amphiploids were obtained by somatic chromosome doubling. These were (i) (G. latifolia, 2n = 40, genome B1B1,) × (G. microphylla, 2n = 40, genome BB) = F1(2n = 40, genome BB1) – 0.1% colchicine treatment (CT) – 2n = 80, genome BBB1B1; (ii) (G. canescens, 2n = 40, genome AA) × G. microphylla, 2n = 40, genome BB) = F1 (2n = 40, genome AB) – (CT) – 2n = 80, genome AABB; (iii) (G. latifolia, 2n = 40, B1B1) × G. canescens, 2n = 40, AA) = F1 (2n = 40, genome AB1) – (CT) – 2n = 80, genome AAB1B1. The segmental allotetraploid BBB1B1 was morphologically similar to the 80-chromosome G. tabacina (WAR), but meiotic pairing data in F1 hybrids did not support the complete genomic affinity. Despite normal diploid-like meiosis in allotetraploids AABB and AAB1B1, AABB was completely fertile, while pod set in AAB1B1 was very sparse. Morphologically, allotetraploid AABB was indistinguishable from the 80-chromosome G. tabacina (NAR) but in their F1 hybrids, the range of univalents at metaphase I was wide (4–44). The allotetraploid AAB1B1 did not morphologically resemble the 80-chromosome G. tabacina (NAR). However, the F1 hybrid of AABB × AAB1B1 showed normal meiosis with an average chromosome association (range) of 1.7 I (0–4) + 39.2 II (38–40). Based on this information, we cannot correctly deduce the diploid progenitor species of the 80-chromosome G. tabacina (NAR). The lack of exact genome homology may be attributed to the geographical isolation, natural mutation, and growing environmental conditions since the inception of 80-chromosome G. tabacina. Thus, it is logical to suggest that the 80-chromosome G. tabacina (NAR) is a complex, probably synthesized from A genome (G. canescens, G. clandestina, G. argyrea, G. tomentella D4 isozyme group) and B genome (G. latifolia, G. microphylla, G. tabacina) species, and the 80-chromosome G. tabacina (WAR) complex was evolved through segmental allopolyploidy from the B genome species.Key words: Glycine spp., allopolyploidy, colchicine, genome, intra- and inter-specific hybridization, polyploid complex.

Characterization of six wheat × Thinopyrum intermedium derivatives by GISH, RFLP, and multicolor GISH

Genome ◽  
2003 ◽  
Vol 46 (3) ◽  
pp. 490-495 ◽  
Author(s):  
F P Han ◽  
G Fedak ◽  
A Benabdelmouna ◽  
K Armstrong ◽  
T Ouellet
Keyword(s):  
Genomic Dna ◽  
Aegilops Tauschii ◽  
Rflp Analysis ◽  
Aegilops Speltoides ◽  
Thinopyrum Intermedium ◽  
B Genome ◽  
A Genome ◽  
Genetic Stocks ◽  
Disomic Addition Lines ◽  
Thinopyrum Elongatum

Restriction fragment length polymorphism (RFLP) analysis and multicolor genomic in situ hybridization (GISH) are useful tools to precisely characterize genetic stocks derived from crosses of wheat (Triticum aestivum) with Thinopyrum intermedium and Thinopyrum elongatum. The wheat × Th. intermedium derived stocks designated Z1, Z2, Z3, Z4, Z5, and Z6 were initially screened by multicolor GISH using Aegilops speltoides genomic DNA for blocking and various combinations of genomic DNA from Th. intermedium, Triticum urartu, and Aegilops tauschii for probes. The probing (GISH) results indicated that lines Z1 and Z3 were alien disomic addition lines with chromosome numbers of 2n = 44. Z2 was a substitution line in which chromosome 2D was substituted by a pair of Th. intermedium chromosomes; this was confirmed by RFLP and muticolour GISH. Z4 (2n = 44) contained two pairs of wheat – Th. intermedium translocated chromosomes; one pair involved A-genome chromosomes, the other involved D- and A-genome chromosomes. Z5 (2n = 44) contained one pair of wheat – Th. intermedium translocated chromosomes involving the D- and A-genome chromosomes of wheat. Z6 (2n = 44) contained one pair of chromosomes derived from Th. intermedium plus another pair of translocated chromosomes involving B-genome chromosomes of wheat. Line Z2 was of special interest because it has some resistance to infection by Fusarium graminearum.Key words: wheat, Thinopyrum intermedium, addition, substitution, and translocation lines, GISH, multicolor GISH, RFLP.

The mosaic of ancestral karyotype blocks in the Sinapis alba L. genome

Genome ◽  
2011 ◽  
Vol 54 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Matthew N. Nelson ◽  
Isobel A.P. Parkin ◽  
Derek J. Lydiate
Keyword(s):  
Genetic Research ◽  
Brassica Species ◽  
Sinapis Alba ◽  
Ancestral Karyotype ◽  
Crop Species ◽  
B Genome ◽  
A Genome ◽  
The Rich ◽  
Conserved Gene ◽  
First Time

The organisation of the Sinapis alba genome, comprising 12 linkage groups (n = 12), was compared with the Brassicaceae ancestral karyotype (AK) genomic blocks previously described in other crucifer species. Most of the S. alba genome falls into conserved triplicated genomic blocks that closely match the AK-defined genomic blocks found in other crucifer species including the A, B, and C genomes of closely related Brassica species. In one instance, an S. alba linkage group (S05) was completely collinear with one AK chromosome (AK1), the first time this has been observed in a member of the Brassiceae tribe. However, as observed for other members of the Brassiceae tribe, ancestral genomic blocks were fragmented in the S. alba genome, supporting previously reported comparative chromosome painting describing rearrangements of the AK karyotype prior to the divergence of the Brassiceae from other crucifers. The presented data also refute previous phylogenetic reports that suggest S. alba was more closely related to Brassica nigra (B genome) than to B. rapa (A genome) and B. oleracea (C genome). A comparison of the S. alba and Arabidopsis thaliana genomes revealed many regions of conserved gene order, which will facilitate access to the rich genomic resources available in the model species A. thaliana for genetic research in the less well-resourced crop species S. alba.

The origin of wheat chromosomes 4A and 4B and their genome reallocation

1983 ◽  
Vol 25 (3) ◽  
pp. 210-214 ◽  
Author(s):  
J. Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Banding Pattern ◽  
The Other ◽  
Evolutionary Lineage ◽  
C Banding ◽  
B Genome ◽  
A Genome

Triticum aestivum chromosome "4A" is, like the B genome chromosomes, extensively heterochromatic while the remaining six A genome chromosomes are not. In the presence of the Ph gene it does not pair with any chromosome of einkorn wheats, T. monococcum and T. urartu, the source of the A genome. It is shown here that the same chromosome is also present in T. timopheevii which represents the other evolutionary lineage of wheats. The "4A" chromosomes of T. timopheevii and T. aestivum pair poorly with each other, like the B genome chromosomes of the two lineages, while the remaining A genome chromosomes, except for one arm, pair relatively well. Hence, in both lineages chromosome "4A" has the attributes of the B genome chromosomes, not of the A genome chromosomes. The C-banding pattern of chromosome "4A" of T. aestivum and T. timopheevii closely resembles the C-banding pattern of a chromosome of T. speltoides and less closely chromosome 4B1 of T. sharonense. On the basis of this and other evidence it is concluded that this chromosome was contributed by a species of the section Sitopsis and, consequently, belongs to the B genome. Additionally, there is evidence that the chromosome that was originally designated "4B" belongs to the A genome.

Diversity of Ethiopian tetraploid wheat germplasm: breeding opportunities for improving grain yield potential and quality traits

2009 ◽  
Vol 7 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Yifru Teklu ◽  
Karl Hammer
Keyword(s):  
Total Variation ◽  
Phenotypic Diversity ◽  
Diversity Index ◽  
Tetraploid Wheat ◽  
Principal Component ◽  
Diversity Indices ◽  
Yield Potential ◽  
Wheat Improvement ◽  
Geographical Regions ◽  
Diversity Studies

In this paper, Shannon–Weaver diversity indices were employed to examine the phenotypic diversity in 271 Ethiopian tetraploid wheat accessions in relation to characters, regions of origin and altitude. Moreover, review of genetic diversity studies in Ethiopian tetraploid wheat was made to explore breeding opportunities. The diversity index varied widely across regions. Among the four altitudinal classes, the highest (0.72) and lowest (0.61) mean diversity indices were observed in altitude classes II and IV, respectively. The diversity index (H′) showed that most traits are polymorphic. The partitioning of the total phenotypic diversity into within- and among-region diversity indicated that 71% of the total variation was attributed to the within-region diversity. Principal component analysis was computed to examine the regional and altitudinal patterns of variation. On regional bases, the first four axes, whose eigenvalues are greater than 1, explained about 82% of the observed phenotypic diversity in the 271 tetraploid wheat accessions. On altitudinal bases, however, only the first two principal components explained 89.7% of the total variation. In general, phenotypic diversity showed considerable differences for each trait in different geographical regions and altitudinal classes which could be utilized in wheat improvement programmes. Breeding opportunities and strategies are suggested.

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