Abstract
Tetraploid Thinopyrum elongatum, which has superior abiotic stress tolerance characteristics, and exhibits resistance to stripe rust, powdery mildew, and Fusarium head blight, is a wild relative of wheat and a promising source of novel genes for wheat improvement. Currently, a high-resolution Fluorescence in situ hybridization (FISH) karyotype of tetraploid Th. elongatum is not available. To develop chromosome-specific FISH-based markers, the hexaploid Trititrigia 8801 and two accessions of tetraploid Th. elongatum were characterized by different repetitive sequences probes. We found that all E-genome chromosomes could be unambiguously identified using a combination of pSc119.2, pTa535, pTa71, and pTa713 repeats, and the E-genome chromosomes of the wild accessions and the partial amphiploid failed to exhibit any significant variation in the probe hybridization patterns. To verify the validation of these markers, the chromosome constitution of eight wheat- Th. elongatum hybrid derivatives were analyzed. We revealed that these probes could quickly detect wheat and tetraploid Th. elongatum chromosomes in hybrid lines. K16-712-1-2 was a 1E (1D) chromosome substitution line, K16-681-4 was a 2E disomic chromosome addition line, K16-562-3 was a 3E, 4E (3D, 4D) chromosome substitution line, K15-1033-8-2 contained one 4E, two 5E, and one 4ES⋅1DL Robertsonian translocation chromosome, and four other lines carried monosomic 4E, 5E, 6E, and 7E chromosome, respectively. Furthermore, the E-genome specific molecular markers analysis corresponded perfectly with the FISH results. The developed FISH markers will facilitate rapid identification of tetraploid Th. elongatum chromosomes in wheat improvement programs and allow appropriate alien chromosome transfer.
Highlights
As one of the most important cultivated cereals, the wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD) grain production was forecast at 754.8 million tonnes in 2017, and ranked second only to maize in the world (FAO, 2017)
After screening and combining Fluorescence in situ hybridization (FISH) probes including (ACT)5, (CTT)5, pSc119.2, pAs1, pTa535, Afa family, pTa71, pTa713, and pTa794, the (ACT)5 and (CTT)5 microsatellites failed to show any signals on any E-genome chromosomes (Figures 1B,C)
The ultimate objective of this study was to set up an E-genome specific FISH karyotype of tetraploid Th. elongatum using different probes, and determine the chromosome constitutions of wheat- tetraploid Th. elongatum progenies
Summary
The progress in wheat breeding is hampered by a relatively narrow range of genetic diversity (Dubcovsky and Dvorak, 2007). Tetraploid Th. elongatum harbors genes that protect against many pathogens and adverse conditions including stripe rust, powdery mildew, FHB, smut, cold, drought, and high salinity (Dvorák et al, 1988; Jauhar and Peterson, 1996; Fedak, 1999). It serves as an important wild gene pool to increase the genetic diversity of common wheat (Guo et al, 2015). Few attempts have been made to transfer the tetraploid Th. elongatum genes into wheat (Chen et al, 2013; Li et al, 2016; Dai et al, 2017a,b)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
