Abstract
Artificial allopolyploids derived from the genera Triticum and Aegilops have been used as genetic resources for wheat improvement and are a classic example of evolution via allopolyploidization. In this study, we investigated chromosomes and subgenome transmission behavior in the newly formed allopolyploid of wheat group via multicolor Fluorescence in situ hybridization (mc-FISH), using pSc119.2, pTa535, and (GAA)7 as probe combinations, to enabled us to precisely identify individual chromosomes in 381 S3 and S4 generations plants derived from reciprocal crosses between Ae. ventricosa (DvDvNvNv) and T. turgidum (AABB). A higher rate of aneuploidy, constituting 66.04–86.41% individuals, was observed in these two early generations. Of the four constituent subgenomes, Dv showed the highest frequency of elimination, followed by Nv and B, while A was the most stable. In addition, structural chromosomal changes occurred ubiquitously in the selfed progenies of allopolyploids. Among the constituent subgenomes, B showed the highest number of aberrations. In terms of chromosomal dynamics, there was no significant association between the chromosomal behavior model and the cytoplasm, with the exception of chromosomal loss in the Dv subgenome. The chromosome loss frequency in the Dv subgenome was significantly higher in the T. turgidum × Ae. ventricosa cross than in the Ae. ventricosa × T. turgidum cross. This result indicates that, although the D subgenome showed great instability, allopolyploids containing D subgenome could probably be maintained after a certain hybridization in which the D subgenome donor was used as the maternal parent at its onset stage. Our findings provide valuable information pertaining to the behavior patterns of subgenomes during allopolyploidization. Moreover, the allopolyploids developed here could be used as potential resources for the genetic improvement of wheat.
Highlights
Common wheat, or bread wheat, (Triticum aestivum L, AABBDD) is one of the most important food crops worldwide, with extensive reports on its speciation
Various frequencies of aneuploidy were detected in the S1 and S2 generations derived from the crosses between several genotypes of Triticum durum (AABB) and Ae. tauschii (DD) (Mestiri et al, 2010), and persistent aneuploidy was found to be associated with nascent allohexaploid wheat (AABBDD) in the S1 to >S20 generations (Zhang et al, 2013a)
To identify every pair of chromosomes originating from T. turgidum and Ae. ventricosa, oligo-nucleotide probes Oligo-pSc119.2, OligopTa535, and Oligo-(GAA)7 were labeled on the 5 -end with 6-carboxyfluorescein (6-FAM), 6-carboxytetramethylrhodamine (Tamra), and Cy5, respectively, and used as described by Tang et al (2014) and Li G. et al (2016) (Invitrogen, Shanghai, China)
Summary
Bread wheat, (Triticum aestivum L, AABBDD) is one of the most important food crops worldwide, with extensive reports on its speciation. Allopolyploidization between tetraploid wheat (AABB) and Aegilops tauschii (DD) occurred about 10,000 years ago, which gave rise to the speciation of modern bread wheat (AABBDD) (Kilian et al, 2007; Marcussen et al, 2014). As a classical sample for the survey of evolution via allopolyploidization, several studies exist on chromosomal behavioral patterns in nascently synthesized allopolyploids of the Triticum tribe, including the crossing of tetraploid or hexaploid wheat with Aegilops and Secale species. Various frequencies of aneuploidy were detected in the S1 and S2 generations derived from the crosses between several genotypes of Triticum durum (AABB) and Ae. tauschii (DD) (Mestiri et al, 2010), and persistent aneuploidy was found to be associated with nascent allohexaploid wheat (AABBDD) in the S1 to >S20 generations (Zhang et al, 2013a). Chromosomal alterations in the D subgenome, which are not directly contributed by wheat or Ae. tauschii, have not been investigated in detail, and it remains uncertain whether the chromosome behavior pattern exhibits cytoplasmdependence
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
