Nuclear Disposition of Alien Chromosome Introgressions into Wheat and Rye Using 3D-FISH.

Area of Science:

• Plant biology
• Genetics
• Cell biology

Background:

• Eukaryotic chromosomes decondense into distinct nuclear domains (chromosome territories, CTs) during interphase.
• Plants, especially those with large genomes, often exhibit Rabl's configuration (telomeres at one pole, centromeres at the other).
• The precise nuclear addresses of individual plant chromosomes remain less understood compared to mammals.

Purpose of the Study:

• To investigate the nuclear disposition of alien rye and barley chromosomes and chromosome arm introgressions into wheat.
• To determine if these introgressed chromosomes occupy defined positions within the nucleus.
• To analyze the influence of chromosome arm length on nuclear positioning.

Main Methods:

• Utilized 3D-Fluorescence In Situ Hybridization (3D-FISH).
• Analyzed nuclear positioning in various somatic tissues of wheat.
• Examined the arrangement of introgressed alien chromosomes and chromosome arms.

Main Results:

• All introgressed chromosomes displayed Rabl's orientation.
• Relative positions of introgressed chromosomes were generally discrete but rarely associated along their entire lengths.
• Chromosome arm length influenced positioning: shorter arms were closer to the nuclear center, longer arms at the periphery.
• Nuclear arrangement was stable across different tissues and cell cycle stages.

Conclusions:

• Alien chromosome introgressions in wheat exhibit Rabl's orientation but have less defined relative positioning.
• Chromosome arm length is a significant factor in determining nuclear location within plant cells.
• The findings contribute to understanding chromosome organization and nuclear architecture in plants.