Single-Nucleus Transcriptome Analysis Provides New Insights Into B Chromosome Elimination in Sorghum

Area of Science:

• Genetics
• Plant Biology
• Epigenetics

Background:

• B chromosomes are dispensable genetic elements found in various organisms.
• Tissue-specific elimination of B chromosomes during embryogenesis is observed in some plant species, including Sorghum purpureosericeum.
• Understanding the molecular mechanisms of B chromosome elimination is crucial for comprehending their evolutionary dynamics.

Purpose of the Study:

• To investigate the transcriptional landscape of embryos during B chromosome elimination in Sorghum purpureosericeum.
• To identify B-linked transcripts and characterize cellular subpopulations involved in B chromosome dynamics.
• To leverage single-nucleus RNA sequencing (snRNA-seq) for high-resolution analysis of B chromosome behavior.

Main Methods:

• Single-nucleus RNA sequencing (snRNA-seq) was performed on Sorghum purpureosericeum embryos.
• Bioinformatic analysis was used to identify B-linked transcripts and cluster nuclei based on transcriptional profiles.
• Comparative analysis of transcriptional profiles across different cellular subpopulations was conducted.

Main Results:

• snRNA-seq successfully detected a higher number of B-linked transcripts compared to previous methods.
• Nuclei with B-specific transcripts were identified and clustered together, revealing distinct subpopulations.
• Three subpopulations with divergent transcriptional profiles were characterized, with one showing patterns indicative of active B chromosome elimination.

Conclusions:

• Single-nucleus RNA sequencing provides unprecedented resolution for studying B chromosome elimination dynamics.
• Distinct transcriptional profiles within embryonic cells offer insights into the molecular processes underlying B chromosome segregation and elimination.
• This study highlights the utility of single-cell approaches in dissecting complex genetic phenomena like B chromosome behavior.