COLD HARDINESS IN Triticum AND Aegilops SPECIES

1985 ◽  
Vol 65 (1) ◽  
pp. 71-77 ◽  
Author(s):  
A. E. LIMIN ◽  
D. B. FOWLER
Keyword(s):  
Winter Wheat ◽  
Common Wheat ◽  
Cold Hardiness ◽  
Diploid Species ◽  
Genetic System ◽  
Aegilops Species ◽  
D Genome ◽  
Genome Species ◽  
Triticum Timopheevi ◽  
A Genome

A total of 237 Triticum and Aegilops accessions were cold-acclimated and screened for cold hardiness. These included 90 A genome accessions (T. monococcum L. and T. beoticum Boiss.), 26 AG genome accessions of T. timopheevi (Zhuk.) Zhuk., 44 D genome accessions of Ae. squarrosa L., and 77 accessions made from 22 Aegilops species. The greatest degree of cold hardiness was found in the polyploid Aegilops species; particularly Ae. cylindrica Host (CD genome). One Ae. cylindrica accession was equal to the hardy winter wheat cultivar Norstar (T. aestivum L., ABD genome). Triticum timopheevi accessions possessed only poor levels of cold hardiness. Two of the diploid progenitor species of common wheat, T. monococcum and Ae. squarrosa, had poor to intermediate levels of cold hardiness. The D genome species was, on average, more hardy than the A genome species. Several polyploids have achieved a level of cold hardiness greater than that found in any of the diploid species. It is speculated that these hardiness levels have been achieved, in part, by the chance incorporation of hardy diploids in the original hybridization. However, the evolution of new genie forms or an integrated genetic system between the genomes of the polyploid was probably equally important to the development of highly cold hardy types. The utility of related species for the improvement of cold hardiness in common wheat is discussed.Key words: Triticum, Aegilops, cold hardiness, winter wheat, interspecific hybridization

scholarly journals Comparative Functional Studies on Two Diploid Cotton Genomes Reveals Functional Differences of Basic Helix-loop-helix Proteins in Arabidopsis Trichome Initiation

2020 ◽  
pp. 1-12
Author(s):  
Anh Phu Nam Bui ◽  
Vimal Kumar Balasubramanian ◽  
Thuan-Anh Nguyen-Huu ◽  
Tuan-Loc Le ◽  
Hoang Dung Tran
Keyword(s):  
Diploid Species ◽  
Natural Phenomenon ◽  
Tetraploid Cotton ◽  
D Genome ◽  
Genome Species ◽  
Functional Studies ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Cotton Species ◽  
A Genome

Background: The cultivated tetraploid cotton species (AD genomes) was originated from two ancestral diploid species (A and D genomes). While the ancestral A-genome species produce spinnable fibers, the D- genome species do not. Cotton fibers are unicellular trichomes originating from seed coat epidermal cells, and currently there is an immense interest in understanding the process of fiber initiation and development. Current knowledge demonstrates that there is a great of deal of resemblance in initiation mechanism between by Arabidopsis trichome and cotton fiber. Methodology: In this study, we performed comparative functional studies between A genome and D-genome species in cotton by using Arabidopsis trichome initiation as a model. Four cotton genes TTG3, MYB2, DEL61 and DEL65 were amplified from A-genome and D-genome species, and transformed into their homolog trichomeless mutants Arabidopsis ttg1, gl1, and gl3egl3, respectively. Results: Our data indicated that the transgenic plants expressing TTG3 and MYB2 genes from A-genome and D-genome species complement the ttg1 and gl1 mutants, respectively. We also discovered complete absences of two functional basic helix loop helix (bHLH) proteins (DEL65/DEL61) in D- diploid species and one (DEL65) that is functional in A-genome species, but not from D-genome species. This observation is consistent with the natural phenomenon of spinnable fiber production in A- genome species and absence in D-genome species.

Chromosomal organization of a sequence related to LTR-like elements of Ty1-copia retrotransposons in Avena species

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 706-713 ◽  
Author(s):  
Concha Linares ◽  
Antonio Serna ◽  
Araceli Fominaya
Keyword(s):  
In Situ Hybridization ◽  
Diploid Species ◽  
D Genome ◽  
Specific Sequence ◽  
Chromosomal Organization ◽  
Intergenomic Translocations ◽  
A Genome ◽  
Slot Blot Analysis ◽  
Copia Retrotransposons

A repetitive sequence, pAs17, was isolated from Avena strigosa (As genome) and characterized. The insert was 646 bp in length and showed 54% AT content. Databank searches revealed its high homology to the long terminal repeat (LTR) sequences of the specific family of Ty1-copia retrotransposons represented by WIS2-1A and Bare. It was also found to be 70% identical to the LTR domain of the WIS2-1A retroelement of wheat and 67% identical to the Bare-1 retroelement of barley. Southern hybridizations of pAs17 to diploid (A or C genomes), tetraploid (AC genomes), and hexaploid (ACD genomes) oat species revealed that it was absent in the C diploid species. Slot-blot analysis suggested that both diploid and tetraploid oat species contained 1.3 × 104 copies, indicating that they are a component of the A-genome chromosomes. The hexaploid species contained 2.4 × 104 copies, indicating that they are a component of both A- and D-genome chromosomes. This was confirmed by fluorescent in situ hybridization analyses using pAs17, two ribosomal sequences, and a C-genome specific sequence as probes. Further, the chromosomes involved in three C-A and three C-D intergenomic translocations in Avena murphyi (AC genomes) and Avena sativa cv. Extra Klock (ACD genomes), respectively, were identified. Based on its physical distribution and Southern hybridization patterns, a parental retrotransposon represented by pAs17 appears to have been active at least once during the evolution of the A genome in species of the Avena genus.Key words: chromosomal organization, in situ hybridization, intergenomic translocations, LTR sequence, oats.

scholarly journals Pervasive hybridizations in the history of wheat relatives

2018 ◽  
Author(s):  
Sylvain Glémin ◽  
Celine Scornavacca ◽  
Jacques Dainat ◽  
Concetta Burgarella ◽  
Véronique Viader ◽  
...  
Keyword(s):  
Methodological Approach ◽  
Diploid Species ◽  
Phylogenomic Analysis ◽  
D Genome ◽  
Species Relationship ◽  
B Genome ◽  
Hybridization Event ◽  
A Genome ◽  
History Of ◽  
Complex Scenario

AbstractBread wheat and durum wheat derive from an intricate evolutionary history of three genomes, namely A, B and D, present in both extent diploid and polyploid species. Despite its importance for wheat research, no consensus on the phylogeny of the wheat clade has emerged so far, possibly because of hybridizations and gene flows that make phylogeny reconstruction challenging. Recently, it has been proposed that the D genome originated from an ancient hybridization event between the A and B genomes1. However, the study only relied on four diploid wheat relatives when 13 species are accessible. Using transcriptome data from all diploid species and a new methodological approach, we provide the first comprehensive phylogenomic analysis of this group. Our analysis reveals that most species belong to the D-genome lineage and descend from the previously detected hybridization event, but with a more complex scenario and with a different parent than previously thought. If we confirmed that one parent was the A genome, we found that the second was not the B genome but the ancestor of Aegilops mutica (T genome), an overlooked wild species. We also unravel evidence of other massive gene flow events that could explain long-standing controversies in the classification of wheat relatives. We anticipate that these results will strongly affect future wheat research by providing a robust evolutionary framework and refocusing interest on understudied species. The new method we proposed should also be pivotal for further methodological developments to reconstruct species relationship with multiple hybridizations.

scholarly journals INCIPIENT GENOME DIFFERENTIATION IN GOSSYPIUM. III. COMPARISON OF CHROMOSOMES OF G. HIRSUTUM AND ASIATIC DIPLOIDS USING HETEROZYGOUS TRANSLOCATIONS

Genetics ◽  
1982 ◽  
Vol 100 (1) ◽  
pp. 89-103
Author(s):  
Margaret Y Menzel ◽  
Clare A Hasenkampf ◽  
James McD Stewart
Keyword(s):  
Upland Cotton ◽  
Diploid Species ◽  
Standard Line ◽  
Preferential Pairing ◽  
D Genome ◽  
Reciprocal Translocations ◽  
Genome Constitution ◽  
Naturally Occurring ◽  
A Genome ◽  
Segregation Ratios

ABSTRACT Hybrids between upland cotton (G. hirsutum, genome constitution 2AhDh) and either A-genome or D-genome diploid species exhibit 26 paired and 13 unpaired chromosomes at metaphase I. The Ah and Dh genomes are therefore considered homoeologous with those of the respective diploids. Previous studies, nevertheless, revealed a low level of ("incipient") differentiation between Dh and various diploid D genomes. The diploid A genomes have been regarded as more closely homologous to Ah on the basis of low preferential pairing and autotetraploid segregation ratios in allohexaploids.—The present study addressed the following questions: Are the diploid A genomes differentiated from Ah in meiotic homology? If so, is the differentiation manifested equally by all 13 chromosomes or is it localized in certain chromosomes?—Three diploid A-genome lines representing G. herbaceum and G. arboreum were hybridized by in ovulo culture of embryos (1) with a standard line of G. hirsutum, which differs from G. herbaceum by two and from G. arboreum by three naturally occurring reciprocal translocations involving chromosomes 1—5, and (2) with six lines homozygous for experimental translocations involving chromosomes 6, 7, 10, 11, 12 and 13. Chiasma frequencies in hybrids were compared with those in appropriate G. hirsutum controls. In every comparison overall chiasma frequencies were slightly lower in the hybrids. Therefore Ah appears to be differentiated from the diploid A genomes. No localized differentiation was detected in chromosomes marked by experimental translocations. The differentiation may be localized mainly in chromosomes 4 and 5.

ANALYSIS OF SPECIES RELATIONSHIPS IN AVENAE BY THIN-LAYER CHROMATOGRAPHY AND DISC ELECTROPHORESIS

1972 ◽  
Vol 14 (2) ◽  
pp. 305-316 ◽  
Author(s):  
H. C. Dass
Keyword(s):  
Thin Layer ◽  
Diploid Species ◽  
Disc Electrophoresis ◽  
Tetraploid Species ◽  
Species Relationships ◽  
D Genome ◽  
Genome Donor ◽  
A Genome ◽  
Layer Chromatography ◽  
Esterase Patterns

Thin-layer chromatographic studies on flavonoids, and disc electrophoretic studies on proteins and esterase isoenzymes were conducted with Avena to determine species relationships and genome homologies. Distinctness of Avena ventricosa and A. pilosa was observed in comparison to other diploid species. Closeness of the diploid species of the A. strigosa group (including hirtula and wiestii) was evident from the similarity of their protein and esterase spectra. The tetraploid species, A. barbata and A. abyssinica, were found to be very close to A. hirtula and A. strigosa, respectively, by TLC studies. Proteins and esterases also showed that the tetraploid species are very close to the A. strigosa group of diploid species. The contribution of a genome by the A. strigosa group to the tetraploids and hexaploids was confirmed. The hexaploids showed different protein and esterase patterns. The involvement of A. ventricosa as the C genome donor to the hexaploids was shown by the protein and esterase spectra. A few extra protein bands observed may have been from the D genome.

Nitrate Reductase Phylogeny of Potato (Solanum sect. Petota) Genomes with Emphasis on the Origins of the Polyploid Species

2009 ◽  
Vol 34 (1) ◽  
pp. 207-219 ◽  
Author(s):  
Flor Rodríguez ◽  
David M. Spooner
Keyword(s):  
Nitrate Reductase ◽  
Sequence Data ◽  
Diploid Species ◽  
Polyploid Species ◽  
Genome Species ◽  
The North ◽  
Potato Germplasm ◽  
Maternal Genome ◽  
Genome Donor ◽  
A Genome

Solanum section Petota is taxonomically difficult, partly because of interspecific hybridization at both the diploid and polyploid levels. There is much disagreement regarding species boundaries and affiliation of species to series. Elucidating the phylogenetic relationships within the polyploids is crucial for an effective taxonomic treatment of the section and for the utilization of wild potato germplasm in breeding programs. We here infer relationships among the potato diploids and polyploids using nitrate reductase (NIA) sequence data in comparison to prior plastid phylogenies and: 1) examine genome types within section Petota, 2) show species in the polyploid series Conicibaccata, Longipedicellata, and in the Iopetalum group to be derived from allopolyploidization, 3) support an earlier hypothesis by confirming S. verrucosum as the maternal genome donor for the polyploid species S. demissum as well as species in the Iopetalum Group, 4) demonstrate that S. verrucosum is the closest relative to the maternal genome donor for species in ser. Longipedicellata, 5) support the close relationship between S. acaule and diploid species from series Megistacroloba and Tuberosa, and 6) show the North and Central American B genome species to be well distinguished from the A genome species of South America.

Giemsa C-banded karyotypes of Avena species

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 627-632 ◽  
Author(s):  
A. Fominaya ◽  
C. Vega ◽  
E. Ferrer
Keyword(s):  
Interspecific Hybrids ◽  
Chromatin Condensation ◽  
Diploid Species ◽  
Divergent Evolution ◽  
Intercalary Heterochromatin ◽  
Banding Patterns ◽  
Genome Species ◽  
C Banding ◽  
A Genome ◽  
C Genome

Giemsa C-banding was used to identify individual somatic chromosomes in eight diploid species of Avena. Two patterns of heterochromatin distribution were found. The chromosomes of five A genome species (A. strigosa, A. hirtula, A. longiglumis, A. damascena, and A. canariensis) possessed mainly telomeric bands, whereas those from three C genome species (A. clauda, A. pilosa, and A. ventricosa) were characterized by higher chromatin condensation and several intercalary heterochromatin bands. The divergent evolution between the two groups is confirmed after C-banding. The unique C-banding patterns of several chromosomes in each species will be a useful tool for the study of meiotic behaviour in interspecific hybrids among Avena spp.Key words: C-banding, Avena, heterochromatin.

Mycorrhizal dependence of modern wheat cultivars and ancestors: a synthesis

1993 ◽  
Vol 71 (3) ◽  
pp. 512-518 ◽  
Author(s):  
B. A. D. Hetrick ◽  
G. W. T. Wilson ◽  
T. S. Cox
Keyword(s):  
Winter Wheat ◽  
Mycorrhizal Fungi ◽  
Growth Response ◽  
Mycorrhizal Symbiosis ◽  
Aegilops Speltoides ◽  
Wheat Cultivars ◽  
D Genome ◽  
A Genome ◽  
Vesicular Arbuscular ◽  
Winter Wheat Cultivars

To supplement previous studies, wheat ancestors with the A, S(B), D, and AB genomes and modern spring and winter wheat cultivars were vernalized for 42 days in a growth chamber prior to transplanting and growth in a greenhouse for 14 weeks. One-half of the seedlings were inoculated with a mixture of equal numbers of spores of six vesicular–arbuscular mycorrhizal fungi at transplanting. Dry weights of plants and component parts were determined. Percent colonization of roots was determined microscopically. Growth response and mycorrhizal dependence were calculated. However, no mycorrhizal dependence was observed in Triticum monococcum PI 266844 and PI 355520 (A genome), Aegilops speltoides 1773 (S(B) genome), or in the AB genome ancestors Triticum carthlicum 2825, Triticum polonicum 2808, Triticum dicoccum 1165, Triticum pyramidale 2809, Triticum orientale 2805, Triticum paleocolchicum 2807, and Triticum persidum 2811 and 2812. Mycorrhizal dependence in the D genome ancestors was more variable. Triticum tauschii var. typica accessions 1649, 1691, 2378, 2448, 2492, 2495, 2528, 2541, and 2567 lacked dependence, whereas T. tauschii var. meyeri 2529 and var. strangulata 2377 and 2452 were dependent on mycorrhizal symbiosis. The spring wheat cultivars Chinese Spring 3008, Spelta 2603, Pavon 76 2980, and Norin 29 3025 and the winter wheat cultivars TAM 200, Wrangler, Saluda, and Karl were not dependent on mycorrhizae, whereas winter wheat cultivars TAM 107 and Century were dependent. When these data are synthesized with previously tested ancestors, landraces, and cultivars, it appears that both dependent and nondependent diploid ancestors with the A, S(B), and D genomes existed, but dependence was lost in tetraploid ancestors. Since no dependence on mycorrhizae has been demonstrated in any AB genome ancestors, the presence of dependence in modern cultivars of the hexaploid ABD genome is probably derived from the D genome. The consistent dependence of wheat cultivars released before 1950 suggests that modern breeding practices have reduced dependence on mycorrhizal symbiosis. The implications of having mycorrhizal colonization in the absence of mycorrhizal dependence (benefit) are discussed. Key words: pathogenesis, growth response, vesicular – arbuscular mycorrhizae.

scholarly journals Systematic Comparisons of Orthologous Selenocysteine Methyltransferase and Homocysteine Methyltransferase Genes from Seven Monocots Species

2015 ◽  
Vol 7 (2) ◽  
pp. 210-216 ◽  
Author(s):  
De-yong ZHAO ◽  
Fu-lai SUN ◽  
Bo ZHANG ◽  
Zhi-qiang ZHANG ◽  
Long-quan YIN
Keyword(s):  
Common Wheat ◽  
Brachypodium Distachyon ◽  
Aegilops Tauschii ◽  
Selenium Deficiency ◽  
D Genome ◽  
Genome Donor ◽  
A Genome ◽  
Selenocysteine Methyltransferase ◽  
Homocysteine Methyltransferase ◽  
Plant Arabidopsis Thaliana

Identifying and manipulating genes underlying selenium metabolism could be helpful for increasing selenium content in crop grain, which is an important way to overcome diseases resulted from selenium deficiency. A reciprocal smallest distance algorithm (RSD) approach was applied using two experimentally confirmed Homocysteine S-Methyltransferases genes (HMT1 and HMT2) and a putative Selenocysteine Methyltransferase (SMT) from dicots plant Arabidopsis thaliana, to explore their orthologs in seven sequenced diploid monocot species: Oryza sativa, Zea mays, Sorghum bicolor, Brachypodium distachyon, Hordeum vulgare, Aegilops tauschii (the D-genome donor of common wheat) and Triticum urartu (the A-genome donor of common wheat). HMT1 was apparently diverged from HMT2 and most of SMT orthologs were the same with that of HMT2 in this study, leading to the hypothesis that SMT and HMT originate from one common ancestor gene. Identifying orthologs provide candidates for further experimental confirmation; also it could be helpful in designing primers to clone SMT or HMT orthologs in other crops.

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