Introgression of Aegilops speltoides segments in Triticum aestivum and the effect of the gametocidal genes

King, Julie; Grewal, Surbhi; Yang, Caiyun; Hubbart-Edwards, Stella; Scholefield, Duncan; Ashling, Stephen; Harper, John; Allen, Alexandra M.; Edwards, Keith J.; Burridge, Amanda J.; King, Ian

doi:10.1093/aob/mcx149

Cited by 37 publications

(45 citation statements)

References 54 publications

(81 reference statements)

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“…muticum, 21% with T. urartu and 29% with Ae. speltoides (Grewal et al 2018a, b;King et al 2017King et al , 2018. In our hands, the low fertility of F 1 hybrids, although they frequently result in the generation of high numbers of introgressions, remains the rate limiting step with many of the wild relatives of wheat.…”

Section: Discussionmentioning

confidence: 77%

“…In contrast, F 1 hybrids between wheat and Am muticum (King et al 2017), Ae. speltoides (King et al 2018), Th. bessarabicum (Grewal et al 2018a), T. urartu (Grewal et al 2018b) and T. timopheevii (Devi et al 2019) all show complete male sterility.…”

Section: Discussionmentioning

confidence: 99%

“…elongatum polymorphic SNPs generated that could be used to identify introgressions as compared to similar work undertaken in other species, e.g. (King et al 2017(King et al , 2018Grewal et al 2018a, b). The generation of a SNP between a wild relative and wheat requires that a base change is identified in the genome(s) of the species in question relative to the equivalent sequences in the three genomes of wheat.…”

Section: Discussionmentioning

confidence: 99%

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Exploiting the genome of Thinopyrum elongatum to expand the gene pool of hexaploid wheat

et al. 2020

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Key message One hundred and thirty four introgressions from Thinopyrum elongatum have been transferred into a wheat background and were characterised using 263 SNP markers. Abstract Species within the genus Thinopyrum have been shown to carry genetic variation for a very wide range of traits including biotic and abiotic stresses and quality. Research has shown that one of the species within this genus, Th. elongatum, has a close relationship with the genomes of wheat making it a highly suitable candidate to expand the gene pool of wheat. Homoeologous recombination, in the absence of the Ph1 gene, has been exploited to transfer an estimated 134 introgressions from Th. elongatum into a hexaploid wheat background. The introgressions were detected and characterised using 263 single nucleotide polymorphism markers from a 35 K Axiom ® Wheat-Relative Genotyping Array, spread across seven linkage groups and validated using genomic in situ hybridisation. The genetic map had a total length of 187.8 cM and the average chromosome length was 26.8 cM. Comparative analyses of the genetic map of Th. elongatum and the physical map of hexaploid wheat confirmed previous work that indicated good synteny at the macro-level, although Th. elongatum does not contain the 4A/5A/7B translocation found in wheat.

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Section: Discussionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Exploiting the genome of Thinopyrum elongatum to expand the gene pool of hexaploid wheat

et al. 2020

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“…Introgression of genetic material from relative species into bread wheat has been used in plant breeding for over 50 years, although classical plant breeding methods to introgress wild relative segments into wheat are both inefficient and time consuming (Ko et al, 2002). Recent availability of SNP based arrays, combined with classical cytogenetic approaches, significantly enhanced our ability to exploit wild relatives (King et al, 2017a, 2017b), using lines carrying a deletion of either the whole of chromosome 5B, or a smaller 70Mb segment ( ph1b ) (Riley and Chapman, 1958; Sears and Okamoto, 1958: Sears, 1977), to increase the level of homoeologous crossovers between wild relatives and wheat chromosomes. Recombination between wild relative chromosomes and wheat chromosomes is, however, still limited.…”

Section: Discussionmentioning

confidence: 99%

Magnesium increases homoeologous crossover frequency inZIP4(Ph1) mutant wheat-wild relative hybrids

Rey

Martín

Smedley

et al. 2018

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28Wild relatives provide an important source of useful traits in wheat breeding. Wheat and wild relative hybrids 29 have been widely used in breeding programs to introduce such traits into wheat. However, successful introgression 30 is limited by the low frequency of homoeologous crossover (CO) between wheat and wild relative chromosomes. 31Hybrids between wheat carrying a 70Mb deletion on chromosome 5B (ph1b) and wild relatives, have been 32 exploited to increase the level of homoeologous CO, allowing chromosome exchange between their 33 chromosomes. In ph1b-rye hybrids, CO number increases from a mean of 1 CO to 7 COs per cell. CO number 34 can be further increased up to a mean of 12 COs per cell in these ph1b hybrids by treating the plants with Hoagland 35 solution. More recently, it was shown that the major meiotic crossover gene ZIP4 on chromosome 5B (TaZIP4-36 B2) within the 70Mb deletion, was responsible for the restriction of homoeologous COs in wheat-wild relative 37 hybrids, confirming the ph1b phenotype as a complete Tazip4-B2 deletion mutant (Tazip4-B2 ph1b). In this study, 38we have identified the particular Hoagland solution constituent responsible for the increased chiasma frequency 39 in Tazip4-B2 ph1b mutant-rye hybrids and extended the analysis to Tazip4-B2 TILLING and CRISPR mutant-Ae 40 variabilis hybrids. Chiasma frequency at meiotic metaphase I, in the absence of each Hoagland solution 41 macronutrient (NH4 H2PO4, KNO3, Ca (NO3)2·4H2O or Mg SO4·7H2O) was analysed. A significant decrease in 42 homoeologous CO frequency was observed when the Mg 2+ ion was absent. A significant increase of 43 homoeologous CO frequency was observed in all analysed hybrids, when plants were irrigated with a 1mM Mg 2+ 44 solution. These observations suggest a role for magnesium supplementation in improving the success of genetic 45 material introgression from wild relatives into wheat. 46 47 48 49 50 51 52 53 54 55 Despite possessing related ancestral genomes (genome AABBDD), bread wheat behaves as a diploid during 56 meiosis. Deletion of chromosome 5B in tetraploid and hexaploid wheat results in a level of incorrect chromosome 57 pairing and exchange, visualised as a low level of multivalents at metaphase I, and homoeologous crossovers 58 (COs) between related chromosomes in wheat-wild relative hybrids (Riley and Chapman, 1958; Sears and 59 Okamoto, 1958). From these observations, it was proposed that chromosome 5B carries a locus termed Pairing 60 homoeologous 1 (Ph1), which evolved on wheat's polyploidisation and restricted chromosome pairing and COs 61 to true homologues (Riley and Chapman, 1958). A hexaploid wheat cv. Chinese Spring (CS) line carrying a 70Mb 62 deletion on the long arm of chromosome 5B (ph1b) has been exploited over the last 40 years to allow exchange 63 between wild relative and wheat chromosomes. Recently, it was shown that on wheat's polyploidisation, a 64 segment of 3B carrying the major crossover gene ZIP4 and a block of heterochromatin, duplicated and inserted 65 between two CDK2-like g...

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“…Thus Ae. caudata provides an important source of genetic variation for agronomically important traits that can be transferred into wheat as has been previously done for other Aegilops species (King et al, 2018; King et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Development of Wheat-Aegilops caudata Introgression Lines and Their Characterisation Using Genome-Specific KASP Markers

Grewal

Othmeni

Walker

et al. 2020

Preprint

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22Aegilops caudata L. [syn. Ae. markgrafii (Greuter) Hammer], a diploid wild relative of wheat 23 (2n = 2x = 14, CC), is an important source for new genetic variation for wheat improvement 24 due to a variety of disease resistance factors along with tolerance for various abiotic stresses. 25 Its practical utilisation in wheat improvement can be facilitated through the generation of 26 genome-wide introgressions leading to a variety of different wheat-Ae. caudata recombinant 27 lines. In this study, we report the generation of nine such wheat-Ae. caudata recombinant lines 28 which were characterized using wheat genome-specific KASP (Kompetitive Allele Specific 29 PCR) markers and multi-colour genomic in situ hybridization (mcGISH). Of these, six lines 30 have stable homozygous introgressions from Ae. caudata and will be used for future trait 31 analysis. Through a combination of molecular and cytological analysis of all the recombinant 32 lines, we were able to physically map 182 KASP markers onto the seven Ae. caudata 33 chromosomes, of which 155 were polymorphic specifically with only one wheat subgenome. 34Comparative analysis of the physical positions of these markers in the Ae. caudata and wheat 35 genomes confirmed that the former had chromosomal rearrangements with respect to wheat, 36 as previously reported. These wheat-Ae. caudata recombinant lines and KASP markers 37 provide a useful genetic resource for wheat improvement with the latter having a wider impact 38 as a tool for detection of introgressions from other Aegilops species into wheat. 39 40 Introgression of Aegilops caudata into wheat 71 diversity in wheat breeding. Over the past decades, however, efforts have been made to study 72 the molecular organisation of the Ae. caudata genome and its homology with wheat 73 homoeologous groups. Friebe et al. (1992) showed that Ae. caudata has a highly asymmetric 74 karyotype distinct from the metacentric and submetacentric chromosomes of most Triticeae 75 species suggesting the distortion of chromosome collinearity compared to wheat. Fluorescence 76 in situ hybridisation (FISH) and molecular marker analysis of flow-sorted C-genome 77 chromosomes confirmed genome rearrangements (Molnár et al., 2016; Molnár et al., 2015). A 78 set of wheat (cv. Alcedo)-Ae. caudata addition lines B-G (Schubert and Blüthner, 1992; 79 Schubert and Blüthner, 1995) have also been characterised extensively in previous studies 80 using cytogenetic markers (Friebe et al., 1992), isozyme analysis (Schmidt et al., 1993), Simple 81 Sequence Repeat (SSR) markers (Gong et al., 2017; Niu et al., 2018; Peil et al., 1998), FISH 82 with cDNA probes (Danilova et al., 2017), Conserved Orthologous Sequence (COS) and PCR-83 based Landmark Unique Gene (PLUG) markers (Gong et al., 2017), and sequential FISH and 84 genomic in situ hybridization (GISH) (Niu et al., 2018). Many of these studies found that the 85 Introgression of Aegilops caudata into wheat Alcedo-Ae. caudata addition lines carried several inversions and translocations although ...

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Introgression of Aegilops speltoides segments in Triticum aestivum and the effect of the gametocidal genes

Cited by 37 publications

References 54 publications

Exploiting the genome of Thinopyrum elongatum to expand the gene pool of hexaploid wheat

Exploiting the genome of Thinopyrum elongatum to expand the gene pool of hexaploid wheat

Magnesium increases homoeologous crossover frequency inZIP4(Ph1) mutant wheat-wild relative hybrids

Development of Wheat-Aegilops caudata Introgression Lines and Their Characterisation Using Genome-Specific KASP Markers

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