Search

The demand for food resources is increasing quickly because human populations are growing; therefore, food security may become one of the largest human challenges of this century. Crop wild relatives (CWRs) are the most valuable plant genetic resources (PGR) for the conservation of genetic diversity in crops. However, climate change is an added pressure on biodiversity, particularly on this valuable group of plants. It is predicted that more than 50% of this group may be lost by 2055 as a result of the effects of climate change. Iran ranks high in the world in its conservation priorities for CWRs. This study investigates the impacts of climate change on Aegilops L. as important CWRs. MaxEnt was applied to predict the spatial distribution of seven Aegilops species under different climatic scenarios (RCP 2.6 and RCP 8.5) of 2050 and 2080. According to the findings, all species exhibited reduction or expansion responses under all of the above-mentioned climatic scenarios. However, the range change was negative for some species (i.e., Aegilops columnaris, Aegilops cylindrica, Aegilops speltoides, Aegilops tauschii [in all scenarios of 2050 and 2080], and Aegilops kotschyi [RCP 2.6 2050 and 2080]), and positive for others (i.e., Aegilops crassa, Aegilops triuncialis [in all scenarios of 2050 and 2080], and Aegilops kotschyi [RCP 8.5 2050 and 2080]). The results of this study emphasize the need for conservation plans for the country's genetic resources, including regular monitoring and assessment of ecological and demographic changes. Integr Environ Assess Manag 2022;18:697-708. © 2021 SETAC.

Triticale (×Triticosecale Wittmack) is a commercial hybrid harboring wheat (Triticum sp.) and rye (Secale cereale L.) genomes. The limited genetic diversity of this crop resulted in the collapse of fungal disease resistance. Leaf rust disease, caused by Puccinia triticina Eriks. is reported to reduce the triticale yield significantly (more than 30%). There is a need to enlarge the genetic variability of this crop including leaf resistance genes. The main aim of this research was to transfer Lr39 and Lr54 leaf rust resistance genes into triticale from Aegilops tauschii and Ae. kotschyi, respectively. A reaction of seedlings of 200 plants of two triticale-Aegilops translocation lines (Bogo-2Dt.2R and Sekundo-2Sk.2R) was compared after inoculation with a natural mixture of P. triticina races, specific to triticale. Before inoculation, each plant was screened using molecular cytogenetics and molecular markers linked to leaf rust resistance genes. Presence of Aegilops chromosome segments was confirmed using genomic in situ hybridization (GISH). Lr39 and Lr54 leaf rust resistance genes were identified using Xgdm35 and S14 molecular markers, respectively. After inoculation, a significant improvement of resistance severity was observed in Sekundo-2Sk.2R in comparison with triticale cv. Sekundo plants. The resistance level of Bogo-2Dt.2R did not differ compared to triticale cv. Bogo plants. It was shown, that Lr39 gene did not increase the leaf rust resistance level of triticale cv. Bogo.

Major fertility restorer locus for Aegilops kotschyi cytoplasm in wheat, Rfk1 , was mapped to chromosome arm 1BS. Most likely candidate gene is TraesCS1B02G197400LC , which is predicted to encode a pectinesterase/pectinesterase inhibitor. Cytoplasmic male sterility (CMS) is widely used for heterosis and hybrid seed production in wheat. Genes related to male fertility restoration in the presence of Aegilops kotschyi cytoplasm have been reported, but the fertility restoration-associated gene loci have not been investigated systematically. In this study, a BC1F1 population derived from a backcross between KTP116A, its maintainer line TP116B, and its restorer line LK783 was employed to map fertility restoration by bulked segregant RNA-Seq (BSR-Seq). A major fertility allele restorer locus for Ae. kotschyi cytoplasm in wheat, Rfk1, was mapped to chromosome arm 1BS, and it was contributed by LK783. Morphological and cytological studies showed that male fertility restoration occurred mainly after the late uninucleate stage. Based on simple sequence repeat and single-nucleotide polymorphism genotyping, the gene locus was located between Xnwafu_6 and Xbarc137 on chromosome arm 1BS. To further isolate the specific region, six Kompetitive allele-specific polymerase chain reaction markers derived from BSR-Seq were developed to delimit Rfk1 within physical intervals of 26.0 Mb. After searching for differentially expressed genes within the candidate interval in the anthers and sequencing analysis, TraesCS1B02G197400LC was identified as a candidate gene for Rfk1 and it was predicted to encode a pectinesterase/pectinesterase inhibitor. Expression analysis also confirmed that it was specifically expressed in the anthers, and its expression level was higher in fertile lines compared with sterile lines. Thus, TraesCS1B02G197400LC was identified as the most likely candidate gene for Rfk1, thereby providing insights into the fertility restoration mechanism for K-type CMS in wheat.

Background Thermo-sensitive male-sterility based on Aegilops kotschyi cytoplasm (K-TCMS) plays an important role in hybrid wheat breeding. This has important possible applications in two-line hybrid wheat breeding but the genetic basis and molecular regulation mechanism related to fertility restoration are poorly understood. In this study, comparative transcriptome profiling based on RNA sequencing was conducted for two near-isogenic lines comprising KTM3315R and its sterile counterpart KTM3315A, a total of six samples (3 repetitions per group), in order to identify fertility restoration genes and their metabolic pathways. Results In total, 2642 significant differentially expressed genes (DEGs) were detected, among which 1238 were down-regulated and 1404 were up-regulated in fertile anthers. Functional annotation enrichment analysis identified important pathways related to fertility restoration, such as carbohydrate metabolism, phenylpropanoid metabolism and biosynthesis, as well as candidate genes encoding pectin methylesterase and flavanone 3-hydroxylase. Moreover, transcription factor analysis showed that a large number of DEGs were mainly involved with the WRKY, bHLH, and MYB transcription factor families. Determination of total soluble sugar and flavonoid contents demonstrated that important metabolic pathways and candidate genes are associated with fertility restoration. Twelve DEGs were selected and detected by quantitative reverse-transcribed PCR, and the results indicated that the transcriptome sequencing results were reliable. Conclusions Our results indicate that identified DEGs were related to the fertility restoration and they proved to be crucial in Aegilops kotschyi cytoplasm. These findings also provide a basis for exploring the molecular regulation mechanism associated with wheat fertility restoration as well as screening and cloning related genes. Electronic supplementary material The online version of this article (10.1186/s12870-019-1824-9) contains supplementary material, which is available to authorized users.

Alien chromosome introgression has become a valuable tool to broaden the genetic variability of crop plants via chromosome engineering. This study details the procedure to obtain monosomic addition and monosomic substitution lines of the triticale carrying 2Skchromosome fromAegilops kotchyiBoiss., which harborsLr54+Yr37leaf and stripe rust-resistant gene loci, respectively. Initially,A. kotschyi×Secale cerealeartificial amphiploids (2n= 6x= 42 chromosomes, UUSSRR) were crossed with triticale cv. “Sekundo” (2n= 6x= 42, AABBRR) in order to obtain fertile offspring. Cyto-molecular analyses of five subsequent backcrossing generations revealed that 2Skchromosome was preferentially transmitted. This allowed for the selection of monosomic 2Skaddition (MA2Sk) lines of triticale. Finally, the 2Sk(2R) substitution plants were obtained by crossing MA2Skwith the nullisomic (N2R) plants of triticale. The presence of 2Skchromosome in subsequent generations of plants was evaluated using SSR markers linked toLr54+Yr37loci. Disease evaluation of the monosomic 2Sk(2R) substitution plants for the reaction to leaf and stripe rust infection were carried out under controlled conditions in a growth chamber. The results showed significant improvement of leaf rust resistance severity of monosomic substitution plants compared with control (“Sekundo”). In contrast, the introgression of theLr54+Yr37loci did not lead to improvement of stripe rust resistance. In summary, the creation of monosomic addition and monosomic substitution lines of triticale is the starting point for the precise and guided transfer ofLr54+Yr37loci. The results showed that the developed materials could be exploited for the development of triticale varieties with resistance to leaf rust.

Engineered chromosomes 1BS and 1RS offer a new alternative in the development of hybrid systems in bread wheat and triticale. In the cytoplasmic male sterility system for hybrid wheat based on the cytoplasm of Triticum timopheevi fertility restoration is difficult, with few good restorer genes available. In the system based on the cytoplasms of Aegilops kotschyi, Ae. uniaristata and Ae. mutica, essentially all chromosomes 1B carry locus Rf multi that restores male fertility; male sterility manifests itself in wheats with the 1RS.1BL translocation where 1BS chromosome arm is missing. To generate male sterile wheats without the 1RS.1BL translocation, the 1BS arm was cytogenetically engineered to replace the segment with Rf multi with two short inserts of rye chromatin. Conversely, to enhance fertility restoration by doubling the number of restorers present for eventual use in wheat and triticale, a region of 1BS with Rf multi was inserted into 1RS. Alloplasmic wheats with Rf multi removed were completely male sterile; alloplasmic wheats with engineered 1RS carrying Rf multi and without normal 1B were male fertile. An exception to the ubiquitous presence of Rf multi is T. spelta var. duhamelianum; four accessions tested in this study gave inconsistent results but some did not restore male fertility. Engineered chromosomes 1BS and 1RS and chromosomes 1B of T. spelta offer a new alternative for practical application of a cytoplasmic male sterility system in the development of hybrid wheat and hexaploid triticale.

To evaluate genetic variation, 27 accessions of allotetraploid species Aegilops kotschyi and Ae. variabilis with the US genome were analyzed using the AFLP, RAPD, and ISSR methods. A total of 316 polymorphic RAPD fragments, 750 polymorphic AFLP fragments, and 234 polymorphic ISSR fragments were obtained. It was demonstrated that the analyzed species were characterized by a considerable level of nuclear genome variation. According to the data of ISSR and RAPD analysis, the average value of the Jaccard similarity coefficient for the accessions of Ae. variabilis from different geographical regions was slightly lower than that for the accessions of Ae. kotschyi. At the same time, AFLP analysis showed no considerable differences in the levels of intraspecific variation of the studied species. Analysis of the summarized RAPD, ISSR, and AFLP marking data in the Structure software program showed that most of the analyzed accessions with high degree of probability could be assigned to one of two groups, the first of which corresponded to Ae. kotschyi and the second corresponded to Ae. variabilis, thereby confirming the species independence of Ae. kotschyi and Ae. variabilis. Accessions k900, k907, k908, and v90 could not with a sufficiently high degree of probability be assigned to one of the species, which possibly was the result of interspecific hybridization. Analysis of the species diversity using different molecular markers made it possible to identify the accessions that were notably different from other accessions of its species.

High molecular weight glutenin subunits (HMWGS) are responsible for dough elasticity and bread making quality of bread wheat. Related wild non-progenitor species, Aegilops kotschyi possesses higher molecular weight x and y glutenin subunits than the bread wheat cultivars. A wheat-Aegilops substitution line with 1U chromosome was used for the transfer of (HMWGS) of 1U to wheat by using pollen radiation hybridization approach. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiling showed different patterns of allelic variations with either the presence or absence of HMWGS, Glu-1A (1, null), Glu-1B (7, 7 + 8, 17 + 18) and Glu-1D (5 + 10, 2 + 12, null). The pollen irradiated wheat-Aegilops derivatives, B-56-1-4-2, B-56-1-4-3, B-14-1 and B-14-2 with Glu1Ux and 1Uy and absence or presence of some Glu-1A and Glu-1B HMWGS showed high micro SDS sedimentation test (MST) values while B-16-1 and B-16-2 had moderate MST values and high protein content. However, B-58-3 with transfer of Glu-1Ux + 1Uy for Glu-1D showed very low MST values indicating that Glu-1Ux + 1Uy enhance MST value only in the presence of Glu1D HMWGS. The transfer/substitution of alien HMW-GS for Glu-1A and or Glu-1B loci only can lead to improved bread making quality of wheat.

Biofortification of bread wheat by the transfer of useful variability of high grain Fe and Zn from Aegilops kotschyi through induced homoeologous pairing is the most feasible approach to alleviate micronutrient malnutrition worldwide. Deficiency of chromosome 5B in interspecific hybrids allows homoeologous pairing and recombination of chromosomes of wheat with those of the related species. The interspecific hybrid plants without 5B chromosome showed much higher chromosome pairing than did the plants with 5B. The F1 plants without 5B chromosome were selected and repeatedly backcrossed with wheat cultivar PBW343. The chromosome number of BC2F1 plants ranged from 43 to 60 with several univalents and multivalents. Molecular markers and GISH analysis confirmed the introgression of U/S chromosomes of Ae. kotschyi and their fragments in wheat. The BC2F2 plants showed up to 125 % increase in Fe and 158 % increase in Zn compared to PBW343 with Lr24 and Yr36. Induced homoeologous pairing in the absence of 5B was found to be an effective approach for transfer of useful variability for enhanced grain Fe and Zn content for biofortification of wheat for high grain micronutrient content.

To transfer the 2S chromosomal fragment(s) of Aegilops kotschyi (2S(k)) into the bread wheat genome which could lead to the biofortification of wheat with high grain iron and zinc content.Wheat-Ae. kotschyi 2A/2S(k) substitution lines with high grain iron and zinc content were used to transfer the gene/loci for high grain Fe and Zn content into wheat using seed irradiation approach.Bread wheat plants derived from 40 krad-irradiated seeds showed the presence of univalents and multivalents during meiotic metaphase-I. Genomic in situ hybridization analysis of seed irradiation hybrid F2 seedlings showed several terminal and interstitial signals indicated the introgression of Ae. kotschyi chromosome segments. This proves the efficacy of seed radiation hybrid approach in gene transfer experiments. All the radiation-treated hybrid plants with high grain Fe and Zn content were analyzed with wheat group 2 chromosome-specific polymorphic simple sequence repeat markers to identify the introgression of small alien chromosome fragment(s).Radiation-induced hybrids showed more than 65% increase in grain iron and 54% increase in Zn contents with better harvest index than the elite wheat cultivar WL711 indicating effective and compensating translocations of 2S(k) fragments into wheat genome.

A “two-line hybrid system” was developed, previously based on thermo-sensitive cytoplasmic male sterility in Aegilops kotschyi (K-TCMS), which can be used in wheat breeding. The K-TCMS line exhibits complete male sterility and it can be used to produce hybrid wheat seeds during the normal wheat-growing season; it propagates via self-pollination at high temperatures. Isobaric tags for relative and absolute quantification-based quantitative proteome and bioinformatics analyses of the TCMS line KTM3315A were conducted under different fertility conditions to understand the mechanisms of fertility conversion in the pollen development stages. In total, 4639 proteins were identified, the differentially abundant proteins that increased/decreased in plants with differences in fertility were mainly involved with energy metabolism, starch and sucrose metabolism, phenylpropanoid biosynthesis, protein synthesis, translation, folding, and degradation. Compared with the sterile condition, many of the proteins that related to energy and phenylpropanoid metabolism increased during the anther development stage. Thus, we suggest that energy and phenylpropanoid metabolism pathways are important for fertility conversion in K-TCMS wheat. These findings provide valuable insights into the proteins involved with anther and pollen development, thereby, helping to further understand the mechanism of TCMS in wheat.

In the present study we aimed to characterize the interspecific hybrids made between Triticum aestivum cv. Pavon monosomic for chromosome 5B with different accessions of Aegilops kotschyi (UUSS) and Aegilops peregrina (UUSS) at cytological, molecular and morphological basis. Molecular analysis using Ph1 locus specific dominant marker and cytological analysis clearly differentiated between F1 hybrids (ABDUS) with and without 5B chromosome. Plants without chromosome 5B showed stunted and bushy growth habit with reduced height and more number of tillers per plant while those with 5B plants showed normal growth. Agreement of morphological observations with the cytological and molecular results indicates that the morphological characteristics could also be used to screen plants without 5B chromosome. The results clearly demonstrated that the absence of chromosome 5B through the use of Pavon monosomic for chromosome 5B can be an efficient way to induce homoeologous pairing between chromosomes of wheat and Aegilops species for precise introgression of useful variability.

Aegiolops kotschyi cytoplasmic male sterile system often results in part of haploid plants in wheat (Triticum aestivum L.). To elucidate the origin of haploid, 235 wheat microsatellite (SSR) primers were randomly selected and screened for polymorphism between haploid (2n = 3x = 21 ABD) and its parents, male-sterile line YM21 (2n = 6x = 42 AABBDD) and male fertile restorer YM2 (2n = 6x = 42 AABBDD). About 200 SSR markers yielded clear bands from denatured PAGE, of which 180 markers have identifiable amplification patterns, and 20 markers (around 8%) resulted in different amplification products between the haploid and the restorer, YM2. There were no SSR markers that were found to be distinguishable between the haploid and the male sterile line YM21. In addition, different distribution of HMW-GS between endosperm and seedlings from the same seeds further confirmed that the haploid genomes were inherited from the maternal parent. After haploidization, 1.7% and 0.91% of total sites were up- and down-regulated...

Fertility-restoring genes, Rfv1, Rfm1 and Rfn1 , respectively, for the male sterile cytoplasms of Aegilops kotschyi, Ae. mutica and Ae. uniaristata to common wheat were located on the same locus of Pavon wheat 1BS arm. The male sterile cytoplasm (plasmon) and the fertility-restoring gene are essential genetic components for breeding hybrid seed crops. This article represents information on the genetic similarity of three Aegilops plasmons usable as the male sterile cytoplasm for hybrid wheat and provides an evidence on the possible genetic unity of three fertility-restoring genes reported for these plasmons by their genetic mapping using the 1BS-1RS recombinant lines of Pavon 76 wheat on to a single subsegment of the 1BS chromosome arm less than 2.9 cM in size: the locus is designated Rf multi , meaning “Restoration of fertility in multiple CMS systems”. Unresolved problems were discussed in the use of the present cytoplasmic male sterility-fertility restoration system for hybrid wheat breeding.

Wheat and its related genotypes show distinct distribution patterns for mineral nutrients in maternal and filial tissues in grains. X-ray-based imaging techniques are very informative to identify genotypes with contrasting tissue-specific localization of different elements. This can help in the selection of suitable genotypes for nutritional improvement of food grain crops. Understanding mineral localization in cereal grains is important for their nutritional improvement. Spatial distribution of mineral nutrients (Mg, P, S, K, Ca, Fe, Zn, Mn and Cu) was investigated between and within the maternal and filial tissues in grains of two wheat cultivars (Triticum aestivum Cv. WH291 and WL711), a landrace (T. aestivum L. IITR26) and a related wild species Aegilops kotschyi, using micro-proton-induced X-ray emission (µ-PIXE) and micro-X-ray fluorescence (µ-XRF). Aleurone and scutellum were major storage tissues for macro (P, K, Ca and Mg) as well as micro (Fe, Zn, Cu and Mn) nutrients. Distinct elemental distribution patterns were observed in each of the four genotypes. A. kotschyi, the wild relative of wheat and the landrace, T. aestivum L. IITR26, accumulated more Zn and Fe in scutellum and aleurone than the cultivated wheat varieties, WH291 and WL711. The landrace IITR26, accumulated far more S in grains, Mn in scutellum, aleurone and embryo region, Ca and Cu in aleurone and scutellum, and Mg, K and P in scutellum than the other genotypes. Unlike wheat, lower Mn and higher Fe, Cu and Zn concentrations were noticed in the pigment strand of A. kotschyi. Multivariate statistical analysis, performed on mineral distribution in major grain tissues (aleurone, scutellum, endosperm and embryo region) resolved the four genotypes into distinct clusters.

A study of four F5 and one BC1F1 Aegilops kotschyi Boiss. x Triticum aestivum L. hybrid lines was conducted to determine their quantitative morphological and qualitative features as well as a molecular investigation was carried out. Observations of ten quantitative traits showed that the F5 hybrid lines exhibited intermediate values between Ae. kotschyi Boiss. and T. aestivum L., or had similar traits to one of the parents. These hybrid lines had a significantly lower number and weight of grains per main spike, main spike fertility and 1000-grain weight than T. aestivum L. cv. ‘Rusałka’. The BC1F1 hybrid line was characterized by wheat-like fertility and phenotype. The F5 hybrid lines were characterized by much higher variability of the analysed morphological traits than T. aestivum L. cv. ‘Rusałka’. Grains of the hybrid lines had higher protein and micronutrient (iron and zinc) content than wheat grains. The presence of DNA fragments specific to Ae. kotschyi Boiss. in the genotypes of the hybrid lines was confirmed by seven ISSR (Inter Simple Sequence Repeats) molecular markers. Two ISSR markers – ISSR23690 and ISSR33650 – were the most effective for germplasm analysis of the hybrid lines. The analysed lines can become a source material for improvement of common wheat T. aestivum L. in crossing programs.

Robertsonian translocations (RobTs) in the progeny of triticale (×Triticosecale Wittmack) plants with monosomic substitution of Aegilops kotschyi chromosome 2Sk (2R) were investigated by fluorescence in-situ hybridization. Chromosome 2Sk of Ae. kotschyi is reported to possess many valuable loci, such as Lr54 + Yr37 leaf and stripe (yellow) rust resistance genes. We used a standard procedure to produce RobTs, which consisted of self-pollination of monosomic triticale plants, carrying 2R and 2Sk chromosomes in monosomic condition. This approach did not result in RobTs. Simultaneously, we succeeded in producing 11 plants carrying 2R.2Sk compensatory RobTs using an alternative approach that utilized ditelosomic lines of triticale carrying 2RS (short arm) and 2RL (long arm) telosomic chromosomes. Identification of molecular markers linked to Lr54 + Yr37 genes in the translocation plants confirmed that these resources can be exploited in current triticale breeding programmes.

Six novel high molecular weight glutenin subunits (HMW-GS) from Aegilops speltoides (SS, 2n = 2x = 14) and Aegilops kotschyi (UUSS, 2n = 4x = 28) were identified by SDS-PAGE and designated as ASy15*, AKx1*, AKx3*, AKx2.3, AKy20* and AKy8*, respectively. Their complete open reading frames (ORFs) were cloned and sequenced by allele-specific PCR (AS-PCR). Sequence comparison demonstrated that these novel genes displayed high single-nucleotide polymorphisms (SNP) and InDel variations. In particular, AKy8* had an extra cysteine residue at position 140 in the central repetitive domain, while AKx2.3 had an unusually long repetitive domain (816 aa), which might have positive effects on gluten quality. Phylogenetic analysis showed that AKx1* and AKx3* belonged to the 1S genome, AKx2.3 to the 1U genome, and AKy20* and AKy8* most likely to the 1S genome. The divergence between the 6 HMW-GS genes from the two Aegilops species and those from Triticum species occurred 4.77–23.54 MYA. The authenticity of these isolated endogenous HMW-GS genes was confirmed through heterologous expression in Escherichia coli and Western blotting.

A ‘‘two-line hybrid system’’ was developed using thermo-sensitive cytoplasmic male sterility (TCMS) from Aegilops kotschyi and is proposed as a means for seed multiplication and production of hybrid wheat. The TCMS line is crossed to a pollinator line during the normal wheat-growing season for production of hybrid wheat seeds, whereas the TCMS line is maintained through self-pollination in an environment with high temperatures. The male sterile wheat line KTP3314A, containing Ae. kotschyi cytoplasm and the short arm of chromosome 1B from Triticum spelta, was studied in different temperature regimes. KTP3314A was completely male sterile under normal wheat growing temperatures (

Key messageBy removing the Rf (multi) locus from chromosome 1BS of wheat via chromosome engineering we were able to generate a resource for the production of male sterile wheats in three new cytoplasms. Cytoplasmic male sterility is an essential component in the development of many hybrid crops. In wheat (Triticum aestivum L.) only the cytoplasm of T. timopheevi cytoplasm has been extensively tested even though many other cytoplasms are also known to produce male sterility. Among them are the cytoplasms of Ae. kotschyi, Ae. uniaristata and Ae. mutica but here male sterility manifests itself only when the 1RS.1BL rye-wheat translocation is present in the nuclear genome. The location of the male fertility restoring gene on the chromosome arm 1BS (Rf (multi) ) has recently been determined using a set of primary recombinants of chromosome arms 1RS with 1BS. Using this knowledge the same recombinants were used to create chromosome arm 1BS in wheat with a small insert from rye that removes the restorer locus. The disomic engineered chromosome 1B1:6 assures male sterility in all three cytoplasms and any standard chromosome 1B in wheat is capable of restoring it. This newly engineered chromosome in combination with the three cytoplasms of Aegilops sp extends the range of possibilities in attempts to create a viable system for hybrid wheat production.

Mitochondrial DNA rearrangements occur very frequently in flowering plants and when close to genes there must be concomitant acquisition of new regulatory cis-elements. To explore whether there might be limits to such DNA shuffling, we have mapped the termini of mitochondrial mRNAs in wheat, a monocot, and compared them to the known positions for counterpart genes in the eudicot Arabidopsis. Nine genes share homologous 3' UTRs over their full-length and for six of them, the termini map very close to the site of wheat/Arabidopsis DNA rearrangements. Only one such case was seen for comparisons of 5' UTRs, and the 5' ends of mRNAs are typically more heterogeneous than 3' termini. Approximately half of the thirty-one wheat mitochondrial transcriptional units are preceded by CRTA promoter-like motifs, and of the potential stem-loop or tRNA-like structures identified as candidate RNA processing/stability signals near the 5' or 3' ends, several are shared with Arabidopsis. Comparison of the mitochondrial gene flanking sequences from normal fertile wheat (Triticum aestivum) with those of Aegilops kotschyi which is the source of mitochondria present in K-type cytoplasmic male sterile wheat, revealed six cases where mRNAs are precluded from sharing full-length homologous UTRs because of genomic reorganization events, and the presence of short repeats located at the sites of discontinuity points to a reciprocal recombination-mediated mode of rearrangement.

A coupled in vitro digestion/Caco-2 model was employed to assess iron bioavailability from wheat Aegilops derivatives selected for high iron and protein contents. The iron content in wheat genotypes used in this study correlated to a great extent with both protein (r = 0.80) and phytate (r = 0.68) contents. The iron bioavailability was based on Caco-2 cell ferritin formation from cooked digests of these derivatives (relative to WL711 control) and correlated positively with dialyzable iron (r = 0.63) and total iron content (r = 0.38) but not with the phytate content. The apparently decreased phytate/iron molar ratios, however, correlated negatively (r = -0.42) with the iron bioavailability, justifying the utilization of these parameters in biofortification programs. Iron bioavailability in the derivatives increased up to 1.5-fold, corresponding to a 1.5-2.2-fold increase observed in iron content over control. These data suggest that biofortification for iron proportionately leading to higher iron bioavailability will be the most feasible and cost-effective approach to combat micronutrient deficiency.

The valuable genes of Aegilops biuncialis, Ae. ovata, Ae. kotschyi, and Ae. variabilis were transferred to rye, by crossing Aegilops-rye amphiploids with tetraploid and diploid substitution rye. The C-banded karyotype of the BC1 and BC2 generations of amphiploids with 4x substitution rye and BC1 with 2x substitution rye showed great variation in chromosome number and composition. In the BC1 generation of amphiploids with 4x and 2x substitution rye, seed set success rate and germination rate varied depending on origin. However, plant sterility in all cross combinations of amphiploids with 4x and 2x substitution rye resulted in their elimination from further experiments in the BC3 and BC2 generations, respectively. In backcrosses of 4x substitution rye with amphiploids Ae. variabilistimes; rye 4x, fertile 4x rye plants containing Aegilops chromatin were produced in the BC2 generation.

Biofortification through genetic manipulation is the best approach for improving micronutrient content of the staple food crops to alleviate hidden hunger, namely, the deficiency of Fe and Zn affecting more than two billion people worldwide. An interspecific hybridization was made between T. aestivum line Chinese Spring (CS) and Aegilops kotschyi accession 3790 selected for high grain iron and zinc concentration. The CS x Ae. kotschyi F(1) hybrid with low chromosome pairing was highly male and female sterile. This was backcrossed with wheat cultivars to get seed set. The selfed BC(1)F(1) and BC(2)F(1) plants with high grain iron and zinc concentration were selected in subsequent generations. The selected derivatives showed 60-136% enhanced grain iron and zinc concentration and 50-120% increased iron and zinc content per seed as compared to the recipient wheat cultivars. Thirteen cytologically stable, fertile and agronomically superior plants with high grain iron and zinc concentrations were selected for molecular characterization. The application of anchored wheat SSR markers, transferable to Ae. kotschyi, to the high grain iron and zinc containing derivatives indicated introgression of group 2 and group 7 chromosomes of Ae. kotschyi. GISH and FISH analysis of some derivatives confirmed the substitution of chromosomes 2S and 7U for their homoeologues of the A genome, suggesting that some of the genes controlling high grain micronutrient content in the Ae. kotschyi accession are on these chromosomes.

Synthetic amphiploids betweenTriticum aestivum(AABBDD) landrace Chinese Spring (PhI) and cultivar WL711 with different accessions ofAegilops kotschyi(UUSlSl) were developed through colchicine treatment of sterile hybrids. TheF1hybrids and amphiploid plants were intermediate between the parents for plant morphology and spike characteristics. Meiotic metaphase chromosome analysis of theF1hybrids (ABDUSl) showed the expected chromosome number (35) and very little but variable homoeologous chromosome pairing. The amphiploids (AABBDDUUSlSl), however, had variable frequency of univalents at meiotic metaphase-I. The SDS–PAGE of high molecular weight glutenin subunits of amphiploids along with the parents showed the presence and expression of all the parental genomes in the amphiploids. The amphiploids with seeds as large as that of wheat cultivars had higher grain, flag leaf and grain ash iron and zinc concentrations than the wheat parents and comparable with those of theirAe. kotschyiparents suggest thatAe. kotschyipossesses a distinctive genetic system for the micronutrient uptake, translocation and sequestration than the wheat cultivars. This could, however, be demonstrated unequivocally only with comprehensive data on biomass, grain yield and harvest index of theAegilopsdonors and the synthetic amphiploids, which is not feasible due to their shattering and hard threshing. The use of amphiploids for the transfer of high iron and zinc concentrations and development of alien addition and substitution lines in wheat is in progress.

Male sterility with Aegilops kotschyi cytoplasm has a great potential in hybrid wheat (Triticum aestivum L.) breeding for its stable sterility and broad-spectrum of restoring gene resources. To further study the genetic mechanism of male sterility with Ae. kotschyi cytoplasm, a male sterile line ms(Kots)-90-110(A) and its near isogenic line BC4F1 (fertility restored by rk5451) were used to construct sterility and fertility cDNA libraries, using the suppression subtractive hybridization (SSH) method. Wheat anthers with pollen mother cells at the dikaryophase were sampled for RNA extraction via microscopic examination. Both cDNA libraries were good in quality with high efficiency of SSH. A total of 120 positive clones were randomly selected and sequenced from the 2 libraries, and 100 high quality sequences were obtained. According to BLAST screening and functional annotation, energy-related genes were identified with high frequencies in the fertility cDNA library, whereas, MADS-box transcriptional factor TaAGL7, ubiquitin-conjugating enzyme, and adenosine diphosphate glucose pyrophosphatase were detected in the sterility cDNA library. The MADS-box transcription factor TaAGL7 played an important role in regulating flower development. The immature spike ubiquitin-conjugating enzyme would probably relate to apoptosis. The expression of adenosine diphosphate glucose pyrophosphatase directly affected starch synthase and the normal supply of energy. The genes detected in the present study are probably important genes associated with the fertility in wheat with Ae. kotschyi cytoplasm.

Grains of 80 accessions of nine species of wild Triticum and Aegilops along with 15 semi-dwarf cultivars of bread and durum wheat grown over 2 years at Indian Institute of Technology, Roorkee, were analyzed for grain iron and zinc content. The bread and durum cultivars had very low content and little variability for both of these micronutrients. The related non-progenitor wild species with S, U and M genomes showed up to 3–4 folds higher iron and zinc content in their grains as compared to bread and durum wheat. For confirmation, two Ae. kotschyi Boiss. accessions were analyzed after ashing and were found to have more than 30% higher grain ash content than the wheat cultivars containing more than 75% higher iron and 60% higher zinc than that of wheat. There were highly significant differences for iron and zinc contents among various cultivars and wild relatives over both the years with very high broad sense heritability. There was a significantly high positive correlation between flag leaf iron and grain iron (r = 0.82) and flag leaf zinc and grain zinc (r = 0.92) content of the selected donors suggesting that the leaf analysis could be used for early selection for high iron and zinc content. ‘Chinese Spring’ (PhI) was used for inducing homoeologous chromosome pairing between Aegilops and wheat genomes and transferring these useful traits from the wild species to the elite wheat cultivars. A majority of the interspecific hybrids had higher leaf iron and zinc content than their wheat parents and equivalent or higher content than their Aegilops parents suggesting that the parental Aegilops donors possess a more efficient system for uptake and translocation of the micronutrients which could ultimately be utilized for wheat grain biofortification. Partially fertile to sterile BC1 derivatives with variable chromosomes of Aegilops species had also higher leaf iron and zinc content confirming the possibility of transfer of required variability. Some of the fertile BC1F3 and BC2F2 derivatives had as high grain ash and grain ash iron and zinc content as that of the donor Aegilops parent. Further work on backcrossing, selfing, selection of fertile derivatives, leaf and grain analyses for iron and zinc for developing biofortified bread and durum wheat cultivars is in progress.

Aegilopsspecies provide an invaluable source of genes for the improvement of cultivated wheats. This paper illustrates how the existing geo-referenced passport data associated withAegilopsspecies can be used to identify gaps in current conservation and also to develop a more systematic conservation strategy for the genus. Taxonomic, ecological, geographic and conservation information for the 22Aegilopsspecies were collated from ICARDA, EURISCO, GRIN and SINGER datasets, synthesized and analysed. The combined database contained 9866 unique geo-referenced observations collected between 1932 and 2004. Patterns of specific distribution based on the germplasm accession data and the predicted distribution using climatic models were compared in conservation gap analysis using GIS tools. Theex situconservation status of each taxon was assessed and used to provide a priority ranking. Futureex situcollection is recommended in Cyprus, Egypt, Greece, Iran, Israel, Libya, Spain, Syria, Tajikistan, Tunisia, Turkey, Turkmenistan and Uzbekistan. The species identified with the highestex situconservation priority are as follows:Aegilops bicornis,Aegilops comosa,Aegilops juvenalis,Aegilops kotschyi,Aegilops peregrina,Aegilops sharonensis,Aegilops speltoides,Aegilops uniaristataandAegilops vavilovii. Patterns of species richness based on the germplasm accession passport data are presented and five complementary regions ofAegilopsdiversity were identified in west Syria and north Lebanon, central Israel, north-west Turkey, Turkmenistan and south France. Within these areas, 16 IUCN-recognized protected areas are found and these are identified as potential sites to establish genetic reserves. However, the premierAegilopshotspots on the Syrian/Lebanese border are not coincident with any existing internationally recognized protected areas, and here there is a need to establish a novel protected area.

The tendency of unpaired meiotic chromosomes to undergo centric misdivision was exploited to translocate leaf rust and stripe rust resistance genes from an Aegilops kotschyi addition chromosome to a group 2 chromosome of wheat. Monosomic and telosoanic analyses showed that the translocation occurred to wheat chromosome arm 2DL. The introgressed region did not pair with the corresponding wheat 2DL telosome during meiosis suggesting that a whole arm may have been transferred. Female transmission of the resistance was about 55% whereas male transmission was strongly preferential (96%). The symbols Lr54 and Yr37 are proposed to designate the new resistance genes.