An official website of the United States government
Abstract The wheat wild relativeAegilops tauschiiwas previously used to transfer theLr42leaf rust resistance gene into bread wheat.Lr42confers resistance at both seedling and adult stages, and it is broadly effective against all leaf rust races tested to date.Lr42has been used extensively in the CIMMYT international wheat breeding program with resulting cultivars deployed in several countries. Here, using a bulked segregant RNA-Seq (BSR-Seq) mapping strategy, we identify three candidate genes forLr42. Overexpression of a nucleotide-binding site leucine-rich repeat (NLR) gene AET1Gv20040300 induces strong resistance to leaf rust in wheat and a mutation of the gene disrupted the resistance. TheLr42resistance allele is rare inAe. tauschiiand likely arose from ectopic recombination. Cloning ofLr42provides diagnostic markers and over 1000 CIMMYT wheat lines carryingLr42have been developed documenting its widespread use and impact in crop improvement.
more »
« less
Registration of Hessian fly‐resistant germplasm KS18WGRC65 carrying H26 in hard red winter wheat ‘Overley’ background
Abstract Hessian fly (HF;Mayetiola destructorSay) causes severe damage to wheat (Triticum aestivumL.) worldwide. Several resistance genes have been identified in wheat and wild relatives; however, HF populations are under strong selection pressure and evolve rapidly to overcome resistance. To ensure the availability of resistance sources, HF‐resistant germplasm KS18WGRC65 (TA5110, Reg. no. GP‐1042, PI 688251) was developed by Wheat Genetics Resource Center at Kansas State University as a breeding stock that carries resistance geneH26fromAegilops tauschiiCoss. KS18WGRC65 is a cytogenetically stable, homozygous, BC3F3:6line derived from the cross betweenAe. tauschiiaccession KU2147 and hard red winter wheat recurrent parent ‘Overley’. KS18WGRC65 exhibited no penalty for yield or other agronomic characters, making it a suitable source of HF resistance for wheat breeding.
more »
« less
- Award ID(s):
- 1822162
- PAR ID:
- 10457041
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Plant Registrations
- Volume:
- 14
- Issue:
- 2
- ISSN:
- 1936-5209
- Format(s):
- Medium: X Size: p. 206-209
- Size(s):
- p. 206-209
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract BACKGROUNDThe wheat stem sawfly (WSS,Cephus cinctus) is a major pest of wheat (Triticum aestivum) and can cause significant yield losses. WSS damage results from stem boring and/or cutting, leading to the lodging of wheat plants. Although solid‐stem wheat genotypes can effectively reduce larval survival, they may have lower yields than hollow‐stem genotypes and show inconsistent solidness expression. Because of limited resistance sources to WSS, evaluating diverse wheat germplasm for novel resistance genes is crucial. We evaluated 91 accessions across five wild wheat species (Triticum monococcum,T. urartu,T. turgidum,T. timopheevii, andAegilops tauschii) and common wheat cultivars (T. aestivum) for antixenosis (host selection) and antibiosis (host suitability) to WSS. Host selection was measured as the number of eggs after adult oviposition, and host suitability was determined by examining the presence or absence of larval infestation within the stem. The plants were grown in the greenhouse and brought to the field for WSS infestation. In addition, a phylogenetic analysis was performed to determine the relationship between the WSS traits and phylogenetic clustering. RESULTSOverall,Ae. tauschii,T. turgidumandT. urartuhad lower egg counts and larval infestation thanT. monococcum, andT. timopheevii.T. monococcum,T. timopheevii,T. turgidum, andT. urartuhad lower larval weights compared withT. aestivum. CONCLUSIONThis study shows that wild relatives of wheat could be a valuable source of alleles for enhancing resistance to WSS and identifies specific germplasm resources that may be useful for breeding. © 2024 The Authors.Pest Management Sciencepublished by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.more » « less
-
Abstract BackgroundPrioritizing wild relative diversity for improving crop adaptation to emerging drought-prone environments is challenging. Here, we combine the genome-wide environmental scans (GWES) in wheat diploid ancestorAegilops tauschii(Ae. tauschii) with allele testing in the genetic backgrounds of adapted cultivars to identify diversity for improving wheat adaptation to water-limiting conditions. ResultsWe evaluate the adaptive allele effects inAe. tauschii-wheat introgression lines phenotyped for multiple traits under irrigated and water-limiting conditions using both unmanned aerial system-based imaging and conventional approaches. The GWES show that climatic gradients alone explain more than half of genomic variation inAe. tauschii, with many alleles associated with climatic factors inAe. tauschiibeing linked with improved performance of introgression lines under water-limiting conditions. We find that the most significant GWES signals associated with temperature annual range in the wild relative are linked with reduced canopy temperature in introgression lines and increased yield. ConclusionsOur results suggest that introgression of climate-adaptive alleles fromAe. tauschiihas the potential to improve wheat performance under water-limiting conditions, and that variants controlling physiological processes responsible for maintaining leaf temperature are likely among the targets of adaptive selection in a wild relative. Adaptive variation uncovered by GWES in wild relatives has the potential to improve climate resilience of crop varieties.more » « less
-
SUMMARY Aegilopsspecies represent the most important gene pool for breeding bread wheat (Triticum aestivum). Thus, understanding the genome evolution, including chromosomal structural rearrangements and syntenic relationships amongAegilopsspecies or betweenAegilopsand wheat, is important for both basic genome research and practical breeding applications. In the present study, we attempted to develop subgenome D‐specific fluorescencein situhybridization (FISH) probes by selecting D‐specific oligonucleotides based on the reference genome of Chinese Spring. The oligo‐based chromosome painting probes consisted of approximately 26 000 oligos per chromosome and their specificity was confirmed in both diploid and polyploid species containing the D subgenome. Two previously reported translocations involving two D chromosomes have been confirmed in wheat varieties and their derived lines. We demonstrate that the oligo painting probes can be used not only to identify the translocations involving D subgenome chromosomes, but also to determine the precise positions of chromosomal breakpoints. Chromosome painting of 56 accessions ofAe. tauschiifrom different origins led us to identify two novel translocations: a reciprocal 3D‐7D translocation in two accessions and a complex 4D‐5D‐7D translocation in one accession. Painting probes were also used to analyze chromosomes from more diverseAegilopsspecies. These probes produced FISH signals in four different genomes. Chromosome rearrangements were identified inAegilops umbellulata,Aegilops markgrafii, andAegilops uniaristata, thus providing syntenic information that will be valuable for the application of these wild species in wheat breeding.more » « less
-
Sachs, M (Ed.)Abstract Aegilops tauschii is the donor of the D subgenome of hexaploid wheat and a valuable genetic resource for wheat improvement. Several reference-quality genome sequences have been reported for A. tauschii accession AL8/78. A new genome sequence assembly (Aet v6.0) built from long Pacific Biosciences HiFi reads and employing an optical genome map constructed with a new technology is reported here for this accession. The N50 contig length of 31.81 Mb greatly exceeded that of the previous AL8/78 genome sequence assembly (Aet v5.0). Of 1,254 super-scaffolds, 92, comprising 98% of the total super-scaffold length, were anchored on a high-resolution genetic map, and pseudomolecules were assembled. The number of gaps in the pseudomolecules was reduced from 52,910 in Aet v5.0 to 351 in Aet v6.0. Gene models were transferred from the Aet v5.0 assembly into the Aet v6.0 assembly. A total of 40,447 putative orthologous gene pairs were identified between the Aet v6.0 and Chinese Spring wheat IWGSC RefSer v2.1 D-subgenome pseudomolecules. Orthologous gene pairs were used to compare the structure of the A. tauschii and wheat D-subgenome pseudomolecules. A total of 223 structural differences were identified. They included 44 large differences in sequence orientation and 25 differences in sequence location. A technique for discriminating between assembly errors and real structural variation between closely related genomes is suggested.more » « less
