The wheat stem sawfly (WSS,
Overall,
This 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.
Hessian fly (HF;
- Award ID(s):
- 1822162
- NSF-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
- Page Range / eLocation ID:
- p. 206-209
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract BACKGROUND 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.RESULTS Ae. tauschii ,T. turgidum andT. urartu had lower egg counts and larval infestation thanT. monococcum , andT. timopheevii .T. monococcum ,T. timopheevii ,T. turgidum , andT. urartu had lower larval weights compared withT. aestivum .CONCLUSION Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. -
more » « less
Abstract The wheat wild relative
Aegilops tauschii was previously used to transfer theLr42 leaf rust resistance gene into bread wheat.Lr42 confers resistance at both seedling and adult stages, and it is broadly effective against all leaf rust races tested to date.Lr42 has 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. TheLr42 resistance allele is rare inAe. tauschii and likely arose from ectopic recombination. Cloning ofLr42 provides diagnostic markers and over 1000 CIMMYT wheat lines carryingLr42 have been developed documenting its widespread use and impact in crop improvement. -
more » « less
Abstract Central to the diversity of wheat products was the origin of hexaploid bread wheat, which added the D-genome of
Aegilops tauschii to tetraploid wheat giving rise to superior dough properties in leavened breads. The polyploidization, however, imposed a genetic bottleneck, with only limited diversity introduced in the wheat D-subgenome. To understand genetic variants for quality, we sequenced 273 accessions spanning the known diversity ofAe. tauschii . We discovered 45 haplotypes inGlu-D1 , a major determinant of quality, relative to the two predominant haplotypes in wheat. The wheat allele2 +12 was found inAe. tauschii Lineage 2, the donor of the wheat D-subgenome. Conversely, the superior quality wheat allele5 +10 allele originated in Lineage 3, a recently characterized lineage ofAe. tauschii , showing a unique origin of this important allele. These two wheat alleles were also quite similar relative to the total observed molecular diversity inAe. tauschii atGlu-D1 .Ae. tauschii is thus a reservoir for uniqueGlu-D1 alleles and provides the genomic resource to begin utilizing new alleles for end-use quality improvement in wheat breeding programs. -
more » « less
Summary Prolamin and resistance gene families are important in wheat food use and in defense against pathogen attacks, respectively. To better understand the evolution of these multi‐gene families, the
DNA sequence of a 2.8‐Mb genomic region, representing an 8.8 cM genetic interval and harboring multiple prolamin and resistance‐like gene families, was analyzed in the diploid grassAegilops tauschii , the D‐genome donor of bread wheat. Comparison with orthologous regions from rice,Brachypodium , and sorghum showed that theAe. tauschii region has undergone dramatic changes; it has acquired more than 80 non‐syntenic genes and only 13 ancestral genes are shared among these grass species. These non‐syntenic genes, including prolamin and resistance‐like genes, originated from various genomic regions and likely moved to their present locationsvia sequence evolution processes involving gene duplication and translocation. Local duplication of non‐syntenic genes contributed significantly to the expansion of gene families. Our analysis indicates that the insertion of prolamin‐related genes occurred prior to the separation of the Brachypodieae and Triticeae lineages. Unlike inBrachypodium , inserted prolamin genes have rapidly evolved and expanded to encode different classes of major seed storage proteins in Triticeae species. Phylogenetic analyses also showed that the multiple insertions of resistance‐like genes and subsequent differential expansion of eachR gene family. The high frequency of non‐syntenic genes and rapid local gene evolution correlate with the high recombination rate in the 2.8‐Mb region with nine‐fold higher than the genome‐wide average. Our results demonstrate complex evolutionary dynamics in this agronomically important region of Triticeae species. -
more » « less
SUMMARY Aegilops species represent the most important gene pool for breeding bread wheat (Triticum aestivum ). Thus, understanding the genome evolution, including chromosomal structural rearrangements and syntenic relationships amongAegilops species or betweenAegilops and wheat, is important for both basic genome research and practical breeding applications. In the present study, we attempted to develop subgenome D‐specific fluorescencein situ hybridization (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. tauschii from 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 diverseAegilops species. 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.
