scholarly journals Cytogenetic evidence supports Avena insularis being closely related to hexaploid oats.

2021 ◽  
Author(s):  
Esther Ferrer ◽  
Araceli Fominaya ◽  
Yolanda Loarce ◽  
Juan M González
Keyword(s):  
Karyotype Analysis ◽  
Tetraploid Species ◽  
D Genome ◽  
Phylogenetic Studies ◽  
Hexaploid Species ◽  
C Genome ◽  
Cytogenetic Evidence ◽  
Simple Sequence ◽  
Direct Ancestor ◽  
Rule Out

Cytogenetic observations, phylogenetic studies and genome analysis using high-density genetic markers have suggested a tetraploid Avena species carrying the C and D genomes (formerly C and A) to be the donor of all hexaploid oats (AACCDD). However, controversy surrounds which of the three extant CCDD tetraploid species - A. insularis , A. maroccana and A. murphyi - is most closely related to hexaploid oats. The present work describes a comparative karyotype analysis of these three CCDD tetraploid species and two hexaploid species, A. sativa and A. byzantina . This involved the use of FISH with six simple sequence repeats (SSRs) with the motifs CT, AAC, AAG, ACG, ATC and ACT, two repeated ribosomal sequences, and C genome-specific repetitive DNA.  The hybridization pattern of A. insularis with oligonucleotide (AC) 10 was also determined and compared with those previously published for A. sativa and A. byzantina . Significant differences in the 5S sites and SSR hybridization patterns of A. murphyi compared to the other CCDD species rule out its being directly involved in the origin of the hexaploids.  In contrast, the repetitive and SSR hybridization patterns shown by the D genome chromosomes, and by most of the C genome chromosomes of A. maroccana and A. insularis , can be equated with the corresponding chromosomes of the hexaploids.  Several chromosome hybridization signals seen for A. insularis , but not for A. maroccana , were shared with the hexaploid oats species, especially with A. byzantina .  These diagnostic signals add weight to the idea that the extant A. insularis , or a direct ancestor of it, is the most closely related progenitor of hexaploid oats. The similarity of the chromosome hybridization patterns of the hexaploids and CCDD tetraploids was taken as being indicative of homology.  A common chromosome nomenclature for CCDD species based on that of the hexaploid species is proposed.

Molecular diversity of the 5S rRNA gene and genomic relationships in the genus Avena (Poaceae: Aveneae)

Genome ◽  
2008 ◽  
Vol 51 (2) ◽  
pp. 137-154 ◽  
Author(s):  
Yuan-Ying Peng ◽  
Yu-Ming Wei ◽  
Bernard R. Baum ◽  
You-Liang Zheng
Keyword(s):  
Molecular Diversity ◽  
Diploid Species ◽  
5S Rdna ◽  
Rrna Gene ◽  
D Genome ◽  
Rdna Sequences ◽  
Unit Classes ◽  
Hexaploid Species ◽  
Unit Class ◽  
C Genome

The molecular diversity of the rDNA sequences (5S rDNA units) in 71 accessions from 26 taxa of Avena was evaluated. The analyses, based on 553 sequenced clones, indicated that there were 6 unit classes, named according to the haplomes (genomes) they putatively represent, namely the long A1, long B1, long M1, short C1, short D1, and short M1 unit classes. The long and short M1 unit classes were found in the tetraploid A. macrostachya , the only perennial species. The long M1 unit class was closely related to the short C1 unit class, while the short M1 unit class was closely related to the long A1 and long B1 unit classes. However, the short D1 unit class was more divergent from the other unit classes. There was only one unit class per haplome in Avena, whereas haplomes in the Triticeae often have two. Most of the sequences captured belonged to the long A1 unit class. Sequences identified as the long B1 unit class were found in the tetraploids A. abyssinica and A. vaviloviana and the diploids A. atlantica and A. longiglumis . The short C1 unit class was found in the diploid species carrying the C genome, i.e., A. clauda, A. eriantha , and A. ventricosa , and also in the diploid A. longiglumis, the tetraploids A. insularis and A. maroccana , and all the hexaploid species. The short D1 unit class was found in all the hexaploid species and two clones of A. clauda. It is noteworthy that in previous studies the B genome was found only in tetraploid species and the D genome only in hexaploid species. Unexpectedly, we found that various diploid Avena species contained the B1 and D1 units. The long B1 unit class was found in 3 accessions of the diploid A. atlantica (CN25849, CN25864, and CN25887) collected in Morocco and in 2 accessions of A. longiglumis (CIav9087 and CIav9089) collected in Algeria and Libya, respectively, whereas only 1 clone of A. clauda (CN21378) had the short D1 unit. Thus there might be a clue as to where to search for diploids carrying the B and D genomes. Avena longiglumis was found to be the most diverse species, possibly harboring the A, B, and C haplomes. The long M1 and short M1 are the unit classes typical of A. macrostachya. These results could explain the roles of A. clauda, A. longiglumis, and A. atlantica in the evolution of the genus Avena. Furthermore, one clone of the tetraploid A. murphyi was found to have sequences belonging to the short D1 unit class, which could indicate that A. murphyi might have been the progenitor of hexaploid oats and not, as postulated earlier, A. insularis. The evolution of Avena did not follow the molecular clock. The path inferred is that the C genome is more ancient than the A and B genomes and closer to the genome of A. macrostachya, the only existing perennial, which is presumed to be the most ancestral species in the genus.

A THIN-LAYER CHROMATOGRAPHIC STUDY OF SOME AMPHIPLOIDS IN AVENA

1971 ◽  
Vol 13 (4) ◽  
pp. 749-759 ◽  
Author(s):  
Tibor Rajhathy ◽  
D. A. Shearer ◽  
E. M. Warner
Keyword(s):  
Thin Layer ◽  
Extraction Time ◽  
Gene Interactions ◽  
Chromatographic Study ◽  
Tetraploid Species ◽  
Linkage Groups ◽  
Hexaploid Species ◽  
Complementary Gene ◽  
C Genome

A thin-layer chromatographic study was carried out using five synthetic Avena amphiploids and their parental genotypes. The Dass-Nybom solvent and an extraction time of 120 hr were found to be optimum for Avena. About 42% of 3 total of 62 spots were common to all, or all but one species, and these were considered characteristic for the genus. The over-all additiveness of the parental spectra was low (32.5%) in the experimental alloploids; therefore, comparisons of total spectra of natural alloploids and their putative progenitors may not be useful in Avena. A number of hybrid spots, due to complementary gene interactions, was detected. Selected spots specific for either the A- or C-genome diploids could be traced in the polyploids. These suggested the presence of the C genome in the new tetraploid species A. magna, and in the hexaploids, and confirmed A. magna as the putative tetraploid ancestor of the hexaploid species. The chromatographic phenotype, due to its large number of well defined traits, may be very useful in studying gene interactions in polyploid Avena and for marking linkage groups in chromosome deficient lines.

CHROMOSOME RELATIONSHIPS BETWEEN THE CULTIVATED OAT AVENA SATIVA (6x) AND A. VENTRICOSA (2x)

1970 ◽  
Vol 12 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Hugh Thomas
Keyword(s):  
Chromosome Pairing ◽  
Avena Sativa ◽  
Diploid Species ◽  
Meiotic Behaviour ◽  
Hexaploid Species ◽  
C Genome

Chromosome pairing in the F1 hybrid between the cultivated oat Avena sativa and a diploid species A. ventricosa, and in the derived amphiploid, shows that the diploid species is related to one of the genomes of the hexaploid species. The amount of chromosome pairing observed in complex interamphiploid hybrids demonstrates further that A. ventricosa is related to the C. genome of A. sativa. However, the chromosomes of the diploid species have become differentiated from that of the C genome of A. sativa and this is readily apparent in the meiotic behaviour of both the F1 hybrid and the amphiploid.

The complete plastome of real yellow wood (Podocarpus latifolius): gene organization and comparison with related species

Holzforschung ◽  
2019 ◽  
Vol 73 (6) ◽  
pp. 525-536
Author(s):  
Josphat K. Saina ◽  
Zhi-Zhong Li ◽  
Andrew W. Gichira ◽  
Sheila Avoga ◽  
Qing-Feng Wang ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Evolutionary History ◽  
Gene Organization ◽  
Mononucleotide Repeat ◽  
Base Pairs ◽  
Protein Coding ◽  
Phylogenetic Studies ◽  
Circular Molecule ◽  
Rna Genes ◽  
Simple Sequence

AbstractPodocarpus latifolius[(Thunb.) R.Br.exMirb.], also known as real yellow wood, is a large evergreen tree with exceptionally high-quality wood. It is a member of the Podocarpaceae family, which includes many species widely grown for wood pulp as well as timber for construction. Despite its importance, studies focusing on its genetic characterization and molecular biology are limited. Therefore, this study reports the complete plastome ofP. latifolius, which is a circular molecule of 134 020 base pairs (bp) in length, lacking a quadripartite structure. TheP. latifoliusplastome encodes 117 unique genes, consisting of 82 protein-coding genes, 31 transfer RNA genes and four ribosomal RNA genes. The analysis showed that the Podocarpaceae plastomes have experienced some intron and gene losses, inversions, and inverted repeat (IR) loss resulting in a diverse plastome organization at the species and genus levels. Therefore, to understand the extent of these genomic rearrangements, more sampling of the Podocarpaceae plastomes is necessary. A total of 149 editing sites were predicted in 28 genes, all of which were C to U conversions. Moreover, a total of 164 simple sequence repeats (SSRs) were identified in theP. latifoliusplastome, the majority being mononucleotide repeat motifs with A/T sequence predominance. Overall, the data obtained in this study will be useful for population genetics, evolutionary history and phylogenetic studies of the species in this genus.

Genome analysis of Thinopyrum caespitosum

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 141-145 ◽  
Author(s):  
Zhi-Wu Liu ◽  
Richard R. -C. Wang
Keyword(s):  
Genome Analysis ◽  
Karyotype Analysis ◽  
Tetraploid Species ◽  
Genomic Constitution ◽  
Meiotic Analyses

Karyotype and meiotic analyses of the triploid hybrids Pseudoroegneria libanotica (Hackel) A. Löve (2n = 2x = 14; SS) × Thinopyrum caespitosum (C. Koch) R. R.-C. Wang (2n = 4x = 28) and T. bessarabicum (Saval &Rayss) A. Löve (2n = 2x = 14; JJ) × T. caespitosum (2n = 4x = 28) were performed to study the genomic constitution of T. caespitosum. Karyotype analysis of T. caespitosum was also carried out. In all karyotypic studies, the observed ratios between the longest and shortest chromosomes in the genome complements of the tetraploid species and triploid hybrids were higher than the hypothetical one based on the assumption that T. caespitosum has both Je and S genomes. This indicates that amphiplasty occurs at both the triploid and tetraploid levels. The hypothesis that T. caespitosum is an autotetraploid, either JJJJ (JJJeJe) or SSSS, is rejected. The meiotic data, 4.83 I + 0.78 rod II + 4.09 ring II + 2.14 III for P. libanotica × T. caespitosum and 5.16 I + 2.71 rod II + 2.16 ring II + 1.99 III for T. bessarabicum × T. caespitosum, support the hypotheses that the former has SSJe and the latter has JJeS as the genome formula. This evidence and that from other relevant hybrids strongly suggest that T. caespitosum is a true allotetraploid with the genome formula JeJeSS.Key words: karyotype, meiosis, phylogeny, amphiplasty, genome, Lophopyrum, Thinopyrum, Agropyron, Pseudoroegneria.

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.

Highly variable ‘Arhar’ simple sequence repeat markers for molecular diversity and phylogenetic studies in pigeonpea [Cajanus cajan(L.) Millisp.]

2012 ◽  
Vol 132 (2) ◽  
pp. 191-196 ◽  
Author(s):  
Sutapa Dutta ◽  
Ajay K. Mahato ◽  
Priti Sharma ◽  
Ranjeet S. Raje ◽  
Tilak R. Sharma ◽  
...  
Keyword(s):  
Cajanus Cajan ◽  
Simple Sequence Repeat ◽  
Molecular Diversity ◽  
Sequence Repeat ◽  
Simple Sequence Repeat Markers ◽  
Phylogenetic Studies ◽  
Simple Sequence

Rust resistance in Triticum cylindricum Ces. (4x, CCDD) and its transfer into durum and hexaploid wheats

Genome ◽  
1995 ◽  
Vol 38 (1) ◽  
pp. 8-16 ◽  
Author(s):  
D. Bai ◽  
G. J. Scoles ◽  
D. R. Knott
Keyword(s):  
Leaf Rust ◽  
Stem Rust ◽  
Hexaploid Wheat ◽  
Rust Resistance ◽  
Addition Line ◽  
Addition Lines ◽  
D Genome ◽  
C Genome ◽  
Translocation Lines ◽  
Disomic Addition Lines

In order to counteract the effects of the mutant genes in races of leaf rust (Puccinia recondita f.sp. tritici Rob. ex Desm.) and stem rust (P. graminis f.sp. tritici Eriks. &Henn.) in wheat, exploration of new resistance genes in wheat relatives is necessary. Three accessions of Triticum cylindricum Ces. (4x, CCDD), Acy1, Acy9, and Acy11, were tested with 10 races each of leaf rust and stem rust. They were resistant to all races tested. Viable F1 plants were produced from the crosses of the T. cylindricum accessions as males with susceptible MP and Chinese Spring ph1b hexaploid wheats (T. aestivum, 6x, AABBDD), but not with susceptible Kubanka durum wheat (T. turgidum var. durum, 4x, AABB), even with embryo rescue. In these crosses the D genome of hexaploid wheat may play a critical role in eliminating the barriers for species isolation during hybrid seed development. The T. cylindricum rust resistance was expressed in the F1 hybrids with hexaploid wheat. However, only the cross MP/Acy1 was successfully backcrossed to another susceptible hexaploid wheat, LMPG-6. In the BC2F2 of the cross MP/Acy1//LMPG-6/3/MP, monosomic or disomic addition lines with resistance to either leaf rust race 15 (infection types (IT) 1=, 1, or 1+; addition line 1) or stem rust race 15B-1 (IT 1 or 1+; addition line 2) were selected. Rust tests and examination of chromosome pairing of the F1 hybrids and the progeny of the disomic addition lines confirmed that the genes for rust resistance were located on the added T. cylindricum C-genome chromosomes rather than on the D-genome chromosomes. The T. cylindricum chromosome in addition line 2 was determined to be chromosome 4C through the detection of RFLPs among the genomes using a set of homoeologous group-specific wheat cDNA probes. Addition line 1 was resistant to the 10 races of leaf rust and addition line 2 was resistant to the 10 races of stem rust, as was the T. cylindricum parent. The added C-genome chromosomes occasionally paired with hexaploid wheat chromosomes. Translocation lines with rust resistance (2n = 21 II) may be obtained in the self-pollinated progeny of the addition lines through spontaneous recombination of the C-genome chromosomes and wheat chromosomes. Such translocation lines with resistance against a wide spectrum of rust races should be potentially valuable in breeding wheat for rust resistance.Key words: wheat, Triticum cylindricum, rust resistance, gene transfer, addition line, molecular cytogenetics.

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