UNLABELLED: Tiller number is a key component of wheat plant architecture having a direct impact on grain yield. Because of their viability, biotic resistance, and abiotic stress tolerance, wild relative species are a valuable gene source for increasing wheat genetic diversity, including yield potential. Agropyron glael, a perennial hybrid of Thinopyrum intermedium and Th. ponticum, was created in the 1930s. Recent genome analyses identified five evolutionarily distinct subgenomes (J, Jst, Jvs, Jr, and St), making A. glael an important gene source for transferring useful agronomical traits into wheat. During a bread wheat × A. glael crossing program, a genetically stable translocation line, WT153397, was developed. Sequential in situ hybridizations (McGISH) with J-, St-, and D-genomic DNA probes and pSc119.2, Afa family, pTa71, and (GAA)7 DNA repeats, as well as molecular markers specific for the wheat 6D chromosome, revealed the presence of a 6DS.6Jvs Robertsonian translocation in the genetic line. Field trials in low-input and high-input breeding nurseries over four growing seasons demonstrated the Agropyron chromosome arm's high compensating ability for the missing 6DL, as spike morphology and fertility of WT153397 did not differ significantly from those of wheat parents, Mv9kr1 and 'Mv Karizma.' Moreover, the introgressed 6Jvs chromosome arm significantly increased the number of productive tillers, resulting in a significantly higher grain yield potential compared to the parental wheat cultivars. The translocated chromosome could be highly purified by flow cytometric sorting due to the intense fluorescent labeling of (GAA)7 clusters on the Thinopyrum chromosome arm, providing an opportunity to use chromosome genomics to identify Agropyron gene variant(s) responsible for the tillering capacity. The translocation line WT153397 is an important genetic stock for functional genetic studies of tiller formation and useful breeding material for increasing wheat yield potential. The study also discusses the use of the translocation line in wheat breeding. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11032-024-01439-y.
- Keywords
- Agropyron glael, FISH, Flow cytometric sorting, GISH, Tillering, Yield potential,
- Publication type
- Journal Article MeSH
To safeguard bread wheat against pests and diseases, breeders have introduced over 200 resistance genes into its genome, thus nearly doubling the number of designated resistance genes in the wheat gene pool1. Isolating these genes facilitates their fast-tracking in breeding programs and incorporation into polygene stacks for more durable resistance. We cloned the stem rust resistance gene Sr43, which was crossed into bread wheat from the wild grass Thinopyrum elongatum2,3. Sr43 encodes an active protein kinase fused to two domains of unknown function. The gene, which is unique to the Triticeae, appears to have arisen through a gene fusion event 6.7 to 11.6 million years ago. Transgenic expression of Sr43 in wheat conferred high levels of resistance to a wide range of isolates of the pathogen causing stem rust, highlighting the potential value of Sr43 in resistance breeding and engineering.
Using COS markers, the study reveals homeologous relationships between tetraploid Agropyron cristatum and bread wheat to support alien introgression breeding of wheat. Crested wheatgrass (Agropyron cristatum L. Gaertn.) is a wild relative of wheat that possesses many genes that are potentially useful in wheat improvement. The species comprises a complex of diploid, tetraploid and hexaploid forms. In this study, wheat-A. cristatum chromosome, telosome and translocation lines were used to characterize syntenic relationships between tetraploid A. cristatum and bread wheat. Prior to mapping COS markers, the cytogenetic stock lines were characterized for fertility and by FISH and GISH for karyotype stability. Out of 328 COS markers selected for the study, 279 consistently amplified products in tetraploid A. cristatum, and, out of these, 139 were polymorphic between tetraploid crested wheatgrass and wheat. Sixty-nine markers were found to be suitable for the detection of tetraploid A. cristatum chromosomes 1P-6P in wheat, ranging from 6 to 17 markers per chromosome. BLASTn of the source ESTs resulted in significant hits for 67 markers on the wheat pseudomolecules. Generally, COS markers of the same homeologous group were detected on similar arms in both Agropyron and wheat. However, some intragenomic duplications and chromosome rearrangements were detected in tetraploid A. cristatum. These results provide new insights into the structure and evolution of the tetraploid A. cristatum genome and will facilitate the exploitation of the wild species for introgression breeding of bread wheat.
- MeSH
- Agropyron genetics growth & development MeSH
- Bread analysis MeSH
- Chromosomes, Plant MeSH
- Genetic Markers * MeSH
- Genome, Plant genetics MeSH
- Genotype MeSH
- Hybridization, Genetic * MeSH
- Chromosome Mapping MeSH
- Triticum genetics growth & development MeSH
- Tetraploidy * MeSH
- Translocation, Genetic MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Genetic Markers * MeSH
