Additional evidence implicating Triticum searsii as the B-genome donor to wheat

Nath, J.; Hanzel, James J.; Thompson, James P.; McNay, James W.

doi:10.1007/bf00499285

Cited by 29 publications

(4 citation statements)

References 24 publications

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“…longissima (Tanaka, 1956; Konarev et al, 1976; Konarev, 1980; Peacock et al, 1981), Ae. searsii (Feldman and Kislev, 1977; Nath et al, 1983, 1984; Kerby et al, 1990; Liu et al, 2003), Ae. sharonensis (Kushnir and Halloran, 1981) or yet unknown species of the Emarginata group (Kerby et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

Evolution of the S-Genomes in Triticum-Aegilops Alliance: Evidences From Chromosome Analysis

Ruban

Бадаева

2018

Front. Plant Sci.

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Five diploid Aegilops species of the Sitopsis section: Ae. speltoides, Ae. longissima, Ae. sharonensis, Ae. searsii, and Ae. bicornis, two tetraploid species Ae. peregrina (= Ae. variabilis) and Ae. kotschyi (Aegilops section) and hexaploid Ae. vavilovii (Vertebrata section) carry the S-genomes. The B- and G-genomes of polyploid wheat are also the derivatives of the S-genome. Evolution of the S-genome species was studied using Giemsa C-banding and fluorescence in situ hybridization (FISH) with DNA probes representing 5S (pTa794) and 18S-5.8S-26S (pTa71) rDNAs as well as nine tandem repeats: pSc119.2, pAesp_SAT86, Spelt-1, Spelt-52, pAs1, pTa-535, and pTa-s53. To correlate the C-banding and FISH patterns we used the microsatellites (CTT)10 and (GTT)9, which are major components of the C-banding positive heterochromatin in wheat. According to the results obtained, diploid species split into two groups corresponding to Emarginata and Truncata sub-sections, which differ in the C-banding patterns, distribution of rDNA and other repeats. The B- and G-genomes of polyploid wheat are most closely related to the S-genome of Ae. speltoides. The genomes of allopolyploid wheat have been evolved as a result of different species-specific chromosome translocations, sequence amplification, elimination and re-patterning of repetitive DNA sequences. These events occurred independently in different wheat species and in Ae. speltoides. The 5S rDNA locus of chromosome 1S was probably lost in ancient Ae. speltoides prior to formation of Timopheevii wheat, but after the emergence of ancient emmer. Evolution of Emarginata species was associated with an increase of C-banding and (CTT)10-positive heterochromatin, amplification of Spelt-52, re-pattering of the pAesp_SAT86, and a gradual decrease in the amount of the D-genome-specific repeats pAs1, pTa-535, and pTa-s53. The emergence of Ae. peregrina and Ae. kotschyi did not lead to significant changes of the S*-genomes. However, partial elimination of 45S rDNA repeats from 5S* and 6S* chromosomes and alterations of C-banding and FISH-patterns have been detected. Similarity of the Sv-genome of Ae. vavilovii with the Ss genome of diploid Ae. searsii confirmed the origin of this hexaploid. A model of the S-genome evolution is suggested.

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Section: Introductionmentioning

confidence: 99%

Evolution of the S-Genomes in Triticum-Aegilops Alliance: Evidences From Chromosome Analysis

Ruban

Бадаева

2018

Front. Plant Sci.

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“…However, poor meiotic pairing between T. speltoides chromosomes and those of hexaploid wheat cast doubt on this hypothesis (Kimber and Athwal, 1972). Subsequently, several other species in section Sitopsis, including T. longissimum (Feldman, 1979), T. searsii (Nath et al, 1983(Nath et al, , 1984, T. bicorne (Sears, 1956), and T. sharonense (Kushnir and Halloran, 1981), have been proposed as donors of the B genome to polyploid wheat. Kerby and Kuspira (1987) have reviewed the often contradictory evidence providing support for each of the Sitopsis species as donors of the B genome.…”

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confidence: 99%

Molecular Evidence for the Origin of the S-derived Genomes of Polyploid Triticum Species

Talbert

Magyar

Lavin

et al. 1991

American Journal of Botany

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The genus Triticum includes several polyploid species that arose due to hybridization between two or more diploid species. Section Sitopsis is comprised of five diploid species given the genome designation S. Four polyploid species are recognized that contain an S or S-derived genome. We have used two repetitive DNA sequences found primarily in the S genomes of Triticum to determine the likely diploid progenitors of the polyploid species. Comparison of restriction fragments that hybridize to probes for these sequences suggests that T. speltoides is distinct from other members of section Sitopsis (i.e., T. longissimum, T. bicorne, T. searsii, and T. sharonense). The S-derived genome of T. aestivum is more closely related to T. speltoides than to the other Sitopsis diploids. The restriction fragment pattern of T. timopheevii is 98% identical to that of T. speltoides, while those of T. kotschyi and T. syriacum are identical to the group of diploids represented by T. longissimum, T. bicorne, T. searsii, and T. sharonense. Our results are compatible with previous molecular and biochemical data regarding relationships among Triticum species containing an S or S-

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“…Studies that are more recent have reported Ae. searsii (termed T. searsii) as the B-genome donor (Nath et al 1983(Nath et al , 1984. Feldman and Levy (2005) provided some explanations on the ambiguous nature of the B-genome, which include: (1) the diploid donor of the B-genome being extant but not yet discovered; (2) the diploid donor of the B-genome undergoing massive genomic changes after the formation of the allotetraploid; and…”

Section: Discussionmentioning

confidence: 99%

Marker utility of miniature inverted-repeat transposable elements for wheat biodiversity and evolution

et al. 2012

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Transposable elements (TEs) account for up to 80% of the wheat genome and are considered one of the main drivers of wheat genome evolution. However, the contribution of TEs to the divergence and evolution of wheat genomes is not fully understood. In this study, we have developed 55 miniature inverted-repeat transposable element (MITE) markers that are based on the presence/absence of an element, with over 60% of these 55 MITE insertions associated with wheat genes. We then applied these markers to assess genetic diversity among Triticum and Aegilops species, including diploid (AA, BB and DD genomes), tetraploid (BBAA genome) and hexaploid (BBAADD genome) species. While 18.2% of the MITE markers showed similar insertions in all species indicating that those are fossil insertions, 81.8% of the markers showed polymorphic insertions among species, subspecies, and accessions. Furthermore, a phylogenetic analysis based on MITE markers revealed that species were clustered based on genus, genome composition, and ploidy level, while 47.13% genetic divergence was observed between the two main clusters, diploids versus polyploids. In addition, we provide evidence for MITE dynamics in wild emmer populations. The use of MITEs as evolutionary markers might shed more light on the origin of the B-genome of polyploid wheat.

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Additional evidence implicating Triticum searsii as the B-genome donor to wheat

Cited by 29 publications

References 24 publications

Evolution of the S-Genomes in Triticum-Aegilops Alliance: Evidences From Chromosome Analysis

Evolution of the S-Genomes in Triticum-Aegilops Alliance: Evidences From Chromosome Analysis

Molecular Evidence for the Origin of the S-derived Genomes of Polyploid Triticum Species

Marker utility of miniature inverted-repeat transposable elements for wheat biodiversity and evolution

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