Precise Identification of Chromosome Constitution and Rearrangements in Wheat–Thinopyrum intermedium Derivatives by ND-FISH and Oligo-FISH Painting

Abstract

Thinopyrum intermedium possesses many desirable agronomic traits that make it a valuable genetic source for wheat improvement. The precise identification of individual chromosomes of allohexaploid Th. intermedium is a challenge due to its three sub-genomic constitutions with complex evolutionary ancestries. The non-denaturing fluorescent in situ hybridization (ND-FISH) using tandem-repeat oligos, including Oligo-B11 and Oligo-pDb12H, effectively distinguished the St, J and JS genomes, while Oligo-FISH painting, based on seven oligonucleotide pools derived from collinear regions between barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), was able to identify each linkage group of the Th. intermedium chromosomes. We subsequently established the first karyotype of Th. intermedium with individual chromosome recognition using sequential ND-FISH and Oligo-FISH painting. The chromosome constitutions of 14 wheat–Th. intermedium partial amphiploids and addition lines were characterized. Distinct intergenomic chromosome rearrangements were revealed among Th. intermedium chromosomes in these amphiploids and addition lines. The precisely defined karyotypes of these wheat–Th. intermedium derived lines may be helpful for further study on chromosome evolution, chromatin introgression and wheat breeding programs.

Identification and introgression of a novel leaf rust resistance gene from Thinopyrum intermedium chromosome 7Js into wheat

“…In this study, molecular marker ampli cation con rmed that Xiaoyan 78829 contains the 7J s chromosome, which was consistent with the nding of Yu et al (2022). Further marker ampli cation suggested that WTT26 carries the 7J s S and WTT11 the 7J s L chromosomes, respectively.…”

Molecular and Cytogenetic Identification of Wheat-Thinopyrum intermedium Double Substitution Line-Derived Progenies for Stripe Rust Resistance

“…Meanwhile, ND-FISH hybridization of Oligo-744 was tested for the chromosome 4J S and 4St in wheat- Th. intermedium partial amphiploid [ 26 ], and we found that the chromosome 4St had strong signals at the telomeric region of the short arm, while the 4J S had two sites on the centromeric and telomeric regions of the long arm ( Figure 1 f,g). The comparative ND-FISH patterns confirmed that the Oligo-pSc119.2 sites of 4J S S had been replaced by the Oligo-744 sites of 4StS to form the chromosome 4St-J S in X479 ( Figure 1 g).…”

“…Chromosome 4St-J S displayed distinct ND-FISH hybridization patterns of the probes Oligo-744 and Oligo-pSc119.2, showing that the formation of the chromosome 4St-J S in X479 involved the Oligo-pSc119.2 sites of 4J S S replaced by the Oligo-744 sites of 4StS at the telomeric region of the short arm. Therefore, our study demonstrated that ND-FISH techniques are highly effective for precise identification and mapping of wheat-alien chromosomal rearrangements, replacing the traditional FISH and GISH methods [ 24 , 25 , 26 ].…”

Genome Analysis of Thinopyrum intermedium and Its Potential Progenitor Species Using Oligo-FISH

“…The recent development of the precise identification of Th. intermedium chromosome compliment [45] and chromosome-specific bulked oligonucleotides for identifying E-genome chromosomes in both Th. bessarabicum and Th.…”