Genomic rearrangement in long-term shoot competent cell cultures of hexaploid wheat |
| |
Authors: | W C Wang D Marshall |
| |
Institution: | (1) Research and Extension Center, Texas A&M University, 17360 Coit Road, 75252-6599 Dallas, Texas |
| |
Abstract: | 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. |
| |
Keywords: | chromosome rearrangement chromosome stability plant regeneration somaclonal variation |
本文献已被 SpringerLink 等数据库收录! |
|