Molecular analysis of the phylogenetic relationships among the diploid <Emphasis Type="Italic">Aegilops</Emphasis> species of the section <Emphasis Type="Italic">Sitopsis</Emphasis>

RAPD analysis was used to study the intraspecific variation and phylogenetic relationships of Sgenome diploid Aegilops species regarded as potential donors of the B genome of cultivated wheat. In total, 21 DNA specimens from six S-genome diploid species were examined. On a dendrogram, Ae. speltoides and Ae. aucheri formed the most isolated cluster. Among the other species, Ae. searsii was the most distant while Ae. longissima and Ae. sharonensis were the closest species. The maximum difference between individual accessions within one species was approximately the same (0.18–0.22) in Ae. bicornis, Ae. longissima, Ae. sharonensis, and Ae. searsii. The difference between the clusters of questionable species Ae. speltoides and Ae. aucheri corresponded to the intraspecific level; the difference between closely related Ae. longissima and Ae. sharonensis corresponded to the interspecific level.     

Genetic Diversity of the Cytoplasm in Triticum and Aegilops. VIII. Fraction I Protein of 39 Cytoplasms

The electrophoretic characteristics of the cytoplasmically controlled large subunit of the Fraction I protein of 36 alloplasmic and three euplasmic control lines are reported. These lines, representing the cytoplasms of 32 Triticum and Aegilops species, had either H- or L-type large subunits in their Fraction I protein; the diploid Triticum and most Aegilops species, including Ae. bicornis and Ae. sharonensis, had the L-type subunits; whereas, all the polyploid Triticum species (emmer, timopheevi, common wheats), Ae. speltoides, Ae. aucheri, and Ae. longissima had H-type subunits. Therefore, section Sitopsis of Aegilops exhibits interspecific heterogeneity. The H-type is believed to have originated in the Sitopsis section from an L-type subunit because of the prevalence of the latter among the diploid species.     

Restriction Fragment Length Polymorphism (RFLP) for protein disulfide isomerase (PDI) gene sequences in Triticum and Aegilops species

RFLP variation revealed by protein disulfide isomerase (PDI) coding gene sequences was assessed in 170 accessions belonging to 23 species of Triticum and Aegilops. PDI restriction fragments were highly conserved within each species and confirmed that plant PDI is encoded either by single-copy sequences or by small gene families. The wheat PDI probe hybridized to single EcoRI or HindIII fragments in different diploid species and to one or two fragments per genome in polyploids. Four Aegilops species in the Sitopsis section showed complex patterns and high levels of intraspecific variation, whereas Ae. searsii possessed single monomorphic fragments. T. urartu and Ae. squarrosa showed fragments with the same mobility as those in the A and D genomes of Triticum polyploid species, respectively, whereas differences were observed between the hybridization patterns of T. monococcum and T. boeoticum and that of the A genome. The single fragment detected in Ae. squarrosa was also conserved in most accessions of polyploid Aegilops species carrying the D genome. The five species of the Sitopsis section showed variation for the PDI hybridization fragments and differed from those of the B and G genomes of emmer and timopheevi groups of wheat, although one of the Ae. speltoides EcoRI fragments was similar to those located on the 4B and 4G chromosomes. The similarity between the EcoRI fragment located on the 1B chromosome of common and emmer wheats and one with a lower hybridization intensity in Ae. longissima, Ae. bicornis and Ae. sharonensis support the hypothesis of a polyphyletic origin of the B genome. Received: 25 June 1999 / Accepted: 14 September 1999     

A comparative analysis of the composition and organization of two subtelomeric repeat families in <Emphasis Type="Italic">Aegilops speltoides</Emphasis>Tausch. and related species

The structural organization and evolution of two tandemly repeated families, Spelt1 and Spelt52, located in the subtelomeric regions of Aegilops speltoides chromosomes were studied. The Spelt1 family of sequences with a monomer length of 178 bp was characterized by cloning and sequence analysis of polymerase chain reaction (PCR) products. Members of the Spelt1 family revealed sequence similarities exceeding 95\%. This conservation has remained despite divergence of species in Aegilops section Sitopsis and after independent multiple amplification events in the genome of Ae. speltoides. Sequences representing the Spelt52 family were cloned, sequenced and compared with other sequences in databases. The Spelt52 repeat family contains monomers of two types, Spelt52.1 and Spelt52.2. The two monomers share a homologous stretch of 280 bp and have two regions without sequence similarity of 96 bp and 110 bp, respectively. PCR analysis was conducted to 15 lines in Ae. speltoidesTausch., Ae. longissimaSchw.&Mushc.,Ae. sharonensisEig.,Ae. bicornis(Forssk)Jaub.&Sp., andAe. searsii Feld.&Kis. using primers to the homologous and non- homologous regions of Spelt52 family. Intraspecies and interspecies differences in the occurrence and abundance of combinations of Spelt52.1 and Spelt52.2 monomers were detected. The use of primers to telomeric and subtelomeric repeats followed by Southern hybridization, cloning, and sequence analysis demonstrated that Spelt1 and Spelt52 are localized close to each other and to telomeric repeats. The efficiency of a PCR approach for the analysis of telomeric/subtelomeric junction regions of chromosomes is discussed.     

Electrophoretic survey of seedling esterases in wheats in relation to their phylogeny

Summary Evolutionary and ontogenetic variation of six seedling esterases of independent genetic control is studied in polyploid wheats and their diploid relatives by means of polyacrylamide gel electrophoresis. Four of them are shown to be controlled by homoeoallelic genes in chromosomes of third, sixth and seventh homoeologous groups.The isoesterase electrophoretic data are considered supporting a monophyletic origin of both the primitive tetraploid and the primitive hexaploid wheat from which contemporary taxa of polyploid wheats have emerged polyphyletically and polytopically through recurrent introgressive hybridization and accumulation of mutations. Ancestral diploids belonging or closely related to Triticum boeoticum, T. urartu, Aegilops speltoides and Ae. tauschii ssp. strangulata are genetically the most suitable genome donors of polyploid wheats. Diploids of the Emarginata subsection of the section Sitopsis, Aegilops longissima s.str., Ae. sharonensis, Ae. searsii and Ae. bicornis, are unsuitable for the role of the wheat B genome donors, being all fixed for the esterase B and D electromorphs different from those of tetraploid wheats.     

The molecular basis of genetic diversity among cytoplasms of Triticum and Aegilops

Summary Many related species and strains of common wheat were compared by matching differences among their mitochondrial genomes with their parent nuclear genomes. We examined three species of Aegilops, section Sitopsis (Ae. bicornis, Ae. sharonensis, and Ae. speltoides), emmer wheat (Triticum dicoccoides, T. dicoccum, and T. durum), common wheat (T. spelta, T. aestivum, and T. compaction), and timopheevi wheat (T. araraticum, T. timopheevi, and T. zhukovskyi). A single source of the cytoplasm was used in all the species, except Ae. speltoides (two sources), T. araraticum (two), and T. aestivum (three). Following restriction endonuclease analyses, the mitochondrial genomes were found to comprise seven types, and a dendrogram showing their genetic relatedness was constructed, based upon the percentage of common restriction fragments. MtDNAs from T. dicoccum, T. durum, T. aestivum, and T. compactum yielded identical restriction fragment patterns; these differed from T. dicoccoides and T. spelta mtDNAs in only 2.3% of their fragments. The fragment patterns of T. timopheevi and T. zhukovskyi were identical, and these differed from T. araraticum mtDNA by only one fragment. In both the emmer-dinkel and timopheevi groups, mitochondrial genome differentiation is evident, suggesting a diphyletic origin of each group. MtDNAs from four accessions of the Sitopsis species of Aegilops differ greatly from one another, but those of Ae. bicornis, Ae. sharonensis, and Ae. searsii, belonging to the same subsection Emarginata, are relatively similar. MtDNAs of timopheevi species are identical, or nearly so, to those of Ae. speltoides accession (09), suggesting that the latter was the cytoplasm donor to the former, polyploid group. The origin of this polyploid group seems to be rather recent in that the diploid and polyploid species possess nearly identical mitochondrial genomes. We cannot determine, with precision, the cytoplasm donor to the emmer-dinkel group. However, our results do suggest that mitochondrial DNAs show larger evolutionary divergence than do the ctDNAs from these same strains.Contribution no. 507 from the Laboratory of Genetics, Faculty of Agriculture, Kyoto University, Japan     

Metaphase I-bound arms frequency and genome analysis in wheat-Aegilops hybrids. 3. Similar relationships between the B genome of wheat and S or S l genomes of Ae. speltoides,Ae. longissima and Ae. sharonensis

The meiotic behaviour of Triticum aestivum × Aegilops speltoides, T. aestivum × Ae. sharonensis and T. aestivum × Ae. longissima tetraploid hybrids (genome constitution ABDS, ABDS ^l , and ABDS ^l , respectively) has been analysed by the C-banding technique. Of the six types of pairing normally occurring, at metaphase I three were recognized: A-D, AD-BS/AD-BS ^l and B-S/B-S ^l . The relative order observed in the low pairing hybrid, A-D> B-S ^l >AD-BS ^l , as well as that found in high-pairing Chinese Spring × Ae. speltoides hybrids, A-D>AD-BS>ß-S, revealed the existence of preferential pairing patterns among the different genomes that are in competition. In all of the hybrids analysed the mean number of bound arms per cell for the A-D type was significantly higher than the mean number of associations between the B and S/S ^l genomes. Usually the relative contribution of each type of pairing is maintained among hybrids with different Aegilops species. These results indicate that the genomes of Ae. speltoides, Ae. sharonensis and Ae. longissima show a similar affinity with the genomes of hexaploid wheat; therefore none of these species can be considered to be a distinct donor of the B genome of wheats.     

Characterization of genetic variation in and phylogenetic relationships among diploid<Emphasis Type="Italic"> Aegilops</Emphasis> species by AFLP: incongruity of chloroplast and nuclear data

Intra- and inter-specific genetic variation was investigated in seven diploid Aegilops species using the amplified fragment length polymorphism (AFLP) technique. Of the seven species, the cross-pollinating Aegilops speltoides and Aegilops mutica showed high levels of intraspecific variation whereas the remaining five self-pollinating species showed low levels. Aegilops bicornis, Aegilops searsii and Ae. speltoides formed one cluster in the dendrograms, while Aegilops caudata and Aegilops umbellulata formed another. Relationships among the species inferred were more consistent with the relationships inferred from studies of chromosome pairing in interspecific hybrids, and previous molecular phylogenetic reconstructions based on nuclear DNA, than they were with those based on molecular plasmon analysis, suggesting that the nuclear genome has evolved differently from the cytoplasmic genome in the genus Aegilops.Communicated by J. Dvorak     

Species relationships and genetic variation in the diploid wheats (Triticum,Aegilops) as revealed by starch gel electrophoresis

Twenty enzyme loci were examined in the diploid species ofTriticum andAegilops for allelic variation by starch gel electrophoresis. SectionSitopsis, including the five species,Ae. speltoides, Ae. lingissima, Ae. sharonensis, Ae. bicornis andAe. searsii form a close subgroup withAe. speltoides slightly removed from the others.T. monococcum s. lat., was found to be closest to the species of theSitopsis group.Ae. comosa, Ae. umbellulata andAe. uniaristata form a second subgroup withAe. caudata most closely related to these species.Ae. squarrosa appears almost equally related to all of the species, showing no special affinity for any one species group. Nineteen out of twenty loci examined were polymorphic with a mean of 6.7 alleles per locus. Species could be, for most loci, characterized by the presence of predominant alleles. A conspicious genetic characteristic ofTriticum-Aegilops is the sharing of these predominant alleles between species. Within species variation is characterized by a diffuse distribution of secondary alleles.     

The genetic control of grain esterases in hexaploid wheat

Summary A comparison of EST-5 grain esterase phenotypes from wheat-alien amphiploid, addition and substitution genotypes, resolved by flat-bed isoelectric focusing identified homoeologous Est-5 loci on chromosome 3H of Hordeum vulgare, 3H^ch of H. chilense, 3S^b of Aegilops bicornis, 3S¹ of Ae. sharonensis and Ae. longissima and 6R of Secale cereale and 6R^m of S. montanum. The Est-5 genes in alien species provide evidence for chromosome homoeology with wheat.     

Homoeologous relationships of Aegilops speltoides chromosomes to bread wheat

 Homoeologous pairing at metaphase I was analysed in the standard-type, ph2b and ph1b hybrids of Triticum aestivum (AABBDD) and Aegilops speltoides (SS). Data from relative pairing affinities were used to predict homoeologous relationships of Ae. speltoides chromosomes to wheat. Chromosomes of both species, and their arms, were identified by C-banding. The Ae. speltoides genotype carried genes that induced a high level of homoeologous pairing in the three types of hybrids analyzed. All arms of the seven chromosomes of the S genome showed normal homoeologous pairing, which implies that no apparent chromosome rearrangements occurred in the evolution of Ae. speltoides relative to wheat. A pattern of preferential pairing of two types, A-D and B-S, confirmed that the S genome is very closely related to the B genome of wheat. Although this pairing pattern was also reported in hybrids of wheat with Ae. longissima and Ae. sharonensis, a different behaviour was found in group 5 chromosomes. In the hybrids of Ae. speltoides, chromosome 5B-5S pairing was much more frequent than 5D-5S, while these chromosome associations reached similar frequencies in the hybrids of Ae. longissima and Ae. sharonensis. These results are in agreement with the hypothesis that the B genome of wheat is derived from Ae. speltoides. Received: 8 January 1998 / Accepted: 4 February 1998     

Variation in the distribution of a genome-specific DNA sequence on chromosomes reveals evolutionary relationships in the Triticum and Aegilops complex

 The present study analyzed the distribution pattern of the Ae. speltoides–derived repetitive clone pGc1R-1 in the Triticum/Aegilops complex. Fluorescence in situ hybridization analysis showed that clone pGc1R-1 is a S-genome-specific repetitive sequence that hybridized to the S-genome of three species in the section Sitopsis, Aegilops speltoides (S), Ae. longissima (S^l), and Ae. sharonensis (S^sh), but not to Ae. bicornis (S^b) and Ae. searsii (S^s), nor to any other diploid Aegilops species. This clone also hybridized to the very closely related G-genome of T. timopheevii subsp. armeniacum and T. timopheevii ssp. timopheevii, but not to the B-genome of T. turgidum and T. aestivum. Hybridization also was observed in the polyploid Aegilops species, Ae. kotschyi (U^kS^k), Ae. peregrina (U^pS^p), and Ae. vavilovii (X^vaD^vaS^va). Large inter- and intraspecific variations were observed. Our results confirm that the S genome is related more to the S^l and S^sh genomes than to the S^b and S^s genomes; there is a greater affinity between the G and S genomes than between the B and S genomes. Mechanisms to account for the variation in the FISH pattern with different genomes include sequence amplification and deletion. Variation in the distribution of this genome-specific DNA sequence, pGc1R-1, on chromosomes can be used to reveal evolutionary relationships in the Triticum and Aegilops complex. Received April 10, 2002; accepted July 12, 2002 Published online: November 28, 2002 Address of the authors: Peng Zhang, Bernd Friebe (e-mail: friebe@ksu.edu), Bikram S. Gill, Wheat Genetics Resource Center, Department of Plant Pathology, 4024 Throckmorton, Plant Sciences Center, Kansas State University, Manhattan, KS 66506-5502, USA.     

Atrazine-resistant cytoplasmic male-sterile-nigra broccoli obtained by protoplast fusion between cytoplasmic male-sterile Brassica oleracea and atrazine-resistant Brassica campestris

Summary By using restriction endonuclease digestion patterns, the degree of intraspecific polymorphism of mitochondrial DNA in four diploid species of wheat and Aegilops, Ae. speltoides, Ae. longissima, Ae. squarrosa, and Triticum monococcum, was assessed. The outbreeding Ae. speltoides was found to possess the highest degree of variability, the mean number of nucleotide substitutions among conspecific individuals being 0.027 substitutions per nucleotide site. A very low degree of mtDNA variation was detected among Ae. longissima accessions, with most of the enzyme-probe combinations exhibiting uniform hybridization patterns. The mean number of substitutions among Ae. longissima individuals was 0.001 substitutions per nucleotide site. The domesticated diploid wheat T. monococcum var. monococcum and its conspecific variant T. monococcum var. boeoticum seem to lack mitochondrial DNA variability altogether. Thus, the restriction fragment pattern can be used as a characteristic identifier of the T. monococcum cytoplasmic genome. Similarly, Ae. squarrosa accessions were found to be genetically uniform. A higher degree of variation among accessions is observed when noncoding sequences are used as probes then when adjacent coding regions are used. Thus, while noncoding regions may contain regulatory functions, they are subject to less stringent functional constraints than protein-coding regions. Intraspecific variation in mitochondrial DNA correlates perfectly with the nuclear variability detected by using protein electrophoretic characters. This correlation indicates that both types of variation are selectively neutral and are affected only by the effective population size.     

Comparative genetic analysis of the Aegilops longissima and Ae. sharonensis genomes with common wheat

Aegilops longissima Schw. et Musch. (2n= 2x=14, S^lS^l) and Aegilops sharonensis Eig. (2n=2x=14, S^lS^l) are diploid species belonging to the section Sitopsis in the tribe Triticeae and potential donors of useful genes for wheat breeding. A comparative genetic map was constructed of the Ae. longissima genome, using RFLP probes with known location in wheat. A high degree of conserved colinearity was observed between the wild diploid and basic wheat genome, represented by the D genome of cultivated wheat. Chromosomes 1S^l, 2S^l, 3S^l, 5S^l and 6S^l are colinear with wheat chromosomes 1D, 2D, 3D, 5D and 6D, respectively. The analysis confirmed that chromosomes 4S^l and 7S^l are translocated relative to wheat. The short arms and major part of the long arms are homoeologous to most of wheat chromosomes 4D and 7D respectively, but the region corresponding to the distal segment of 7D was translocated from 7S^lL to the distal region of 4S^lL. The map and RFLP markers were then used to analyse the genomes and added chromosomes in a set of ’Chinese Spring’ (CS)/Ae. longissima chromosome additions. The study confirmed the availability of disomic CS/Ae. longissima addition lines for chromosomes 1S^l, 2S^l, 3S^l, 4S^l and 5S^l. An as yet unpublished set of Ae. sharonensis chromosome addition lines were also available for analysis. Due to the gametocidal nature of Ae. sharonensis chromosomes 2S^l and 4S^l, additions 1S^l, 3S^l, 5S^l, 6S^l and 7S^l were produced in a (4D)4S^l background, and 2S^l and 4S^l in a euploid wheat background. The analysis also confirmed that the 4/7 translocation found in Ae. longissima was not present in Ae. sharonensis although the two wild relatives of wheat are considered to be closely related. The phenotypes of the Ae. sharonensis addition lines are described in an Appendix. Received: 28 September 2000 / Accepted: 19 January 2001     

The specific activity of ribulose-1,5-bisphosphate carboxylase in relation to genotype in wheat

The specific activity of ribulose-1,5-bisphosphate carboxylase (RuBPCase; EC 4.1.1.39) in crude extracts of leaves from euploid, amphiploid and alloplasmic lines of wheat fell into high or low categories (3.75 or 2.70 mol·mg^–1·min^–1, 30°C). For the alloplasmic lines, where the same hexaploid nuclear genome was substituted into different cytoplasms, the specific activity of RuBPCase was consistent with the type of cytoplasm (high for the B and S cytoplasms and low for the A and D cytoplasms). There was no evidence from the euploid and amphiploid lines that small subunits encoded in different nuclear genomes influenced the specific activity. High specific activity was conferred by possession of the chloroplast genome of the B-type cytoplasm which encodes the large subunit of RuBPCase. All lines with a cytoplasm derived from the Sitopsis section of wheat, with the exception of Aegilops longissima and A. speltoides 18940, had RuBPCase with high specific activity. In contrast with the euploid lines of A. longissima, the alloplasmic line containing A. longissima cytoplasm from a different source had RuBPCase with high specific activity. The difference in specific activity found here in-vitro was not apparent in-vivo when leaf gas exchange was measured.Abbreviation RuBP(Case) ribulose-1,5-bisphosphate (carboxylase)     

NADP-dependent aromatic alcohol dehydrogenase in polyploid wheats and their diploid relatives. On the origin and phylogeny of polyploid wheats

Summary The three major isoenzymes of the NADP-dependent aromatic alcohol dehydrogenase (ADH-B), distinguished in polyploid wheats by means of polyacrylamide gel electrophoresis, are shown to be coded by homoeoalleles of the locus Adh-2 on short arms of chromosomes of the fifth homoeologous group. Essentially codominant expression of the Adh-2 homoeolleles of composite genomes was observed in young seedlings of hexaploid wheats (T. aestivum s.l.) and tetraploid wheats of the emmer group (T. turgidum s.l.), whereas only the isoenzyme characteristic of the A genome is present in the seedlings of the timopheevii-group tetraploids (T. timopheevii s.str. and T. araraticum).The slowest-moving B³ isoenzyme of polyploid wheats, coded by the homoeoallele of the B genome, is characteristic of the diploid species Aegilops speltoides S.l., including both its awned and awnless forms, but was not encountered in Ae. bicornis, Ae. sharonensis and Ae. longissima. The last two diploids, as well as Ae. tauschii, Ae. caudata, Triticum monococcum s.str., T. boeoticum s.l. (incl. T. thaoudar) and T. urartu all shared a common isoenzyme coinciding electrophoretically with the band B² controlled by the A and D genome homoeoalleles in polyploid wheats. Ae. bicomis is characterized by the slowest isoenzyme, B⁴, not found in wheats and in the other diploid Aegilops species studied.Two electrophoretic variants of ADH-B, B¹ and B², considered to be alloenzymes of the A genome homoeoallele, were observed in T. dicoccoides, T. dicoccon, T. turgidum. s.str. and T. spelta, whereas B² was characteristic of T. timopheevii s.l. and only B¹ was found in the remaining taxa of polyploid wheats. The isoenzyme B¹, not encountered among diploid species, is considered to be a mutational derivative which arose on the tetraploid level from its more ancestral form B² characteristic of diploid wheats.The implication of the ADH-B isoenzyme data to the problems of wheat phylogeny and gene evolution is discussed.     

A chromosome-specific sequence common to the B genome of polyploid wheat and Aegilops searsii

A low-copy, non-coding chromosome-specific DNA sequence, isolated from common wheat, was physically mapped to the distal 19% region of the long arm of chromosome 3B (3BL) of common wheat. This sequence, designated WPG118, was then characterized by Southern hybridization, PCR amplification and sequence comparison using a large collection of polyploid wheats and diploid Triticum and Aegilops species. The data show that the sequence exists in all polyploid wheats containing the B genome and absent from those containing the G genome. At the diploid level, it exists only in Ae. searsii, a diploid species of section Sitopsis, and not in other diploids including Ae. speltoides, the closest extant relative to the donor of the B genome of polyploid wheat. This finding may support the hypothesis that the B-genome of polyploid wheat is of a polyphyletic origin, i.e. it is a recombined genome derived from two or more diploid Aegilops species.     

CHy-banding patterns and chromatin organization inAegilops andTriticum species (Poaceae)

The distribution of CHy-banded heterochromatin was studied in the chromosomes ofAegilops longissima, Ae. speltoides, Triticum monococcum, andT. turgidum. Interphase nuclei were measured after Feulgen staining at different thresholds of optical density; the curves so obtained indicated the relationship among the species with respect to the different fractions of the genomic DNA. The karyological and cytophotometric analyses indicate differences betweenAe. speltoides andAe. longissima, the latter species being enriched in heterochromatin. Similar results were demonstrated for the genusTriticum, in whichT. turgidum showed more heterochromatin when compared withT. monococcum. The results suggest that the B genome of the cultivated wheats possesses a type of heterochromatin that resembles the type present inAe. longissima.     

Evidence for AEGILOPS SHARONENSIS Eig as the Donor of the B Genome of Wheat

A number of lines of evidence are advanced for the candidacy of Aegilops sharonensis Eig as the donor of the B genome of wheat. The cytoplasm of Ae. sharonensis is compatible with tetraploid wheat Triticum turgidum dicoccoides, as evidenced by the high level of chromosome pairing and fertility of the amphiploid Ae. sharonensis x T. turgidum dicoccoides. Ae. sharonensis chromosomes exhibit high levels of pairing with those of the B genome of wheat in hybrids with Ph-deficient hexaploid wheat and low levels of homoeologous pairing with T. monococcum chromosomes.——The amphidiploid between Ae. sharonensis and T. monococcum is very similar to T. turgidum dicoccoides in spike, spikelet and grain morphology. The karyotype of Ae. sharonensis resembles more closely that of extrapolated B genome karyotypes of wheat than do the karyotypes of other proposed B-genome donor species of Aegilops. Because of distinctiveness in cytological affinity and karyotype morphology between Ae. sharonensis and Ae. longissima, a separate genome symbol S^sh is proposed for the former species.     

Electrophoretic and molecular analysis of alpha-gliadins inAegilops species (Poaceae) belonging to the D genome cluster and in their putative progenitors

The D genome cluster includes six allopolyploidAegilops species having as pivotal genome that ofAegilops squarrosa. Alpha-gliadins, endosperm proteins coded by multigenic families, have been analyzed in the D genome species cluster and in their putative progenitors. They can be present or weakly expressed when analyzed in acid polyacrylamide gel electrophoresis. Molecular analysis has shown the possibility to distinguish subsp.strangulata from subsp.eusquarrosa and to confirm the presence ofAe. caudata and ofAe. umbellulata in the polyploidsAe. cylindrica andAe. juvenalis, respectively. Finally, introgression fromAe. longissima orAe. searsii in tetraploid and hexaploidAe. crassa, Ae. juvenalis, andAe. vavilovii is supposed.