Summary
By use of a method for regenerating wheat plants (Triticum aestivum L.) from cells from long-term suspension culture, the chromosome complement and stability of cultured cells of cv. Mustang were examined. Massive chromosome restructuring and genomic rearrangements were detected by HCl−KOH-Giemsa banding techniques. Chromosome structural variations involved mainly heterochromatin and centromeric regions. These included B genome chromosome elimination; heterochromatin amplification; megachromosomes and extrachromosomal DNA particles; translocations and deletions; telocentric, dicentric, and multicentric chromosomes; and somatic pairing and crossing over. At least 65 break-fusion sites were identified. Most of the sites were located in the B genome chromosomes (42 sites, 64.6%); 36.9% (20 sites) were located in the A genome chromosomes; and the fewest (3 sites, 4.6%) were detected in the D genome. Most of the chromosome break-fusion is in the heterochromatin and centromeric regions. The B genome chromosomes appeared to be eliminated nonrandomly, and the stability of the genome may vary among the genotypes and depend on culture duration. We also checked chromosome number of 1-year-old shoot-competent cells. Only 20% of the cells still had 2n=42 chromosomes. Most of the cells (60%) were hyperploid. These observed variations describe the types of tissue-culture-induced variations and suggest the unsuitability of using wheat cells from long-term cultures for genetic transformation experiments.
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Wang, W.C., Marshall, D. Genomic rearrangement in long-term shoot competent cell cultures of hexaploid wheat. In Vitro Cell Dev Biol – Plant 32, 18–25 (1996). https://doi.org/10.1007/BF02823008
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DOI: https://doi.org/10.1007/BF02823008