Plasticity in Triticeae centromere DNA sequences: a wheat × tall wheatgrass (decaploid) model

Abstract

Centromeres mediate chromosome attachment to microtubules and maintain the integrity of chromosomes for proper segregation of the sister chromatids during cell division. Advances in the assembly of Triticeae genome sequences combined with the capacity to recover hybrid species derived from very distantly related species provides potential experimental systems for linking retrotransposon amplification and repositioning of centromeres via non-mendelian inheritance in partial amphiploid breeds. The decaploid tall wheatgrass (Thinopyrum ponticum) is one of the most successfully used perennial species in wheat breeding for generating translocation lines with valuable agronomic traits. We found that wheat centromere retrotransposons CRW and Quinta widely occur within the tall wheatgrass genome. In addition, one of the genome donors to Th. ponticum, Pseudoroegneria stipifolia (StSt), has been shown to have Abigail and a satellite repeat, CentSt. We also found two other centromeric retrotransposons, Abia and CL135 in Th. ponticum by ChIPseq. Examination of partial amphiploid lines that were generated in the 1970s demonstrated extensive modification in centromere sequences using CentSt, Abigail and Abia as probes. We also detected that St-genome chromosomes were more enriched with Abigail and CentSt, whereas E-genome chromosomes were enriched with CRW and Quinta in tall wheatgrass and its closer relatives. It can be concluded that bursts of transposition of retrotransposons and repositioning of centromeres via non-mendelian segregation are common in partial amphiploids derived from interspecific hybrids. Practically speaking, our study reveals that the existence of homologous centromere functional sequences in both a donor and its receptor can substantially contribute to the successful transfer of alien genes into crop species.

New insights into homoeologous copy number variations in the hexaploid wheat genome

“…By contrast, in autopolyploids or paleo‐autopolyploids, such as poplar ( Populus trichocarpa ) and pear ( Pyrus bretschneideri ), subgenome dominance is absent and genes tend to be evenly lost between the two subgenomes (Li et al., 2019; Liu et al., 2017). In wheat, some rapid changes following polyploidization have been reported, including chromosomal rearrangements, epigenetic changes or TE‐related shift in centromere position (Badaeva, Dedkova, Pukhalskyi, & Zelenin, 2015; Dvorak et al., 2018; Jiao et al., 2018; Li et al., 2013; Liu et al., 2009; Shaked, Kashkush, Ozkan, Feldman, & Levy, 2001; Zhao et al., 2019). However, whether the wheat genome experiences subgenome dominance or biased fractionation is still a matter of debate.…”

Comparative Characterization of Pseudoroegneria libanotica and Pseudoroegneria tauri Based on Their Repeatome Peculiarities

“…Pericentromeric localization has been shown for CentSt, S17, and S170 from Ps. stipifolia [ 47 , 49 ]. STlib_117 signals from Ps.…”

“…They are widely used for karyotyping chromosomes, studying chromosomal rearrangements, and analyzing the genomic composition of allo- and autopolyploids and wide hybrids using fluorescence in situ hybridization (FISH) [ 38 , 39 , 40 , 41 , 42 ]. Comparative characteristics between Triticeae species can be studied by comparing the copy numbers of repeating elements [ 43 ], by comparing the distribution patterns across chromosomes and genomes [ 44 , 45 , 46 , 47 ], or by using a combination of both approaches [ 48 , 49 ].…”

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

“…The CENH3 is an essential component of the kinetochore complex of active centromeres, and the mitotic interphase cells are ideal for demonstrating co-localization of CENH3 and centromere repetitive DNA sequences, although the centromere repeats may change extremely rapidly [ 41 , 42 ]. In wheat-alien interspecific hybridization, the wheat- Thinopyrum partial amphiploids containing typical centromeric repeats were well co-localized with CENH3 [ 43 ]. In the present study, the substitution line X479 displayed chromosomal distribution of CENH3 in wheat and the CENH3 peptide generated distinct signals in the centromeric regions of 1St and 4St-J S chromosomes ( Figure 5 a,c), as well as the progenies with 1StS.1BL, 1BS.1StL and 4BS.4J S L, which were detected using immunostaining experiments ( Figure 5 e).…”