Accumulating Heterozygous Deleterious Mutations in Conserved Soybean Germplasm over Successive Regenerations

Area of Science:

• Plant genetics
• Conservation biology
• Molecular biology

Background:

• Long-term conservation of plant germplasm is essential but can lead to the accumulation of deleterious mutations.
• Understanding mutation accumulation dynamics in conserved germplasm is crucial for effective management.

Purpose of the Study:

• To identify and characterize deleterious genetic variants in soybean accessions conserved since 1972.
• To investigate the relationship between mutation burden and conservation parameters like years in conservation and regeneration cycles.

Main Methods:

• Seed-based RNA-Seq analysis of 190 diverse soybean accessions.
• Identification and characterization of deleterious genetic variants.
• Statistical analysis of mutation burdens (total, heterozygous, homozygous) and their correlation with conservation features.

Main Results:

• 588 deleterious variants were identified, mostly weakly or mildly detrimental.
• Total and heterozygous mutation burdens increased significantly with conservation years and regeneration cycles.
• Homozygous mutation burden did not correlate with conservation duration or regeneration frequency.
• Mutation burden showed negative correlations with expressed gene counts and RNA integrity numbers (RINs).

Conclusions:

• Soybean germplasm experiences an accumulation of deleterious mutations, predominantly heterozygous, during long-term conservation and regeneration.
• Mutation accumulation negatively impacts gene expression and RNA quality.
• Findings provide empirical evidence for managing and conserving plant germplasm more effectively.