An epigenetic breeding system in soybean for increased yield and stability

Area of Science:

• Plant Science
• Epigenetics
• Crop Breeding

Background:

• Epigenetic variation influences plant adaptive traits, but direct exploitation methods are limited.
• RNAi suppression of MutS HOMOLOG1 (MSH1) induces developmental reprogramming and methylome changes in plants.
• MSH1 suppression leads to heritable 'memory' effects, independent of transgenes, enhancing trait variation in progeny.

Purpose of the Study:

• To evaluate the MSH1 system's potential for generating agronomically valuable epigenetic variation in soybean.
• To investigate the MSH1-induced epigenetic changes' impact on yield-related traits and stability in soybean.

Main Methods:

• Developed MSH1 epigenetic populations in soybean by crossing with msh1-acquired memory lines.
• Assessed yield-related traits (pods per plant, seed weight, maturity) in glasshouse and field trials.
• Analyzed progeny generations (epi-F2:4 to epi-F2:6) for trait performance, yield stability, and gene expression patterns.

Main Results:

• MSH1 epigenetic lines exhibited increased variance in yield traits and enhanced seed yield in early generations (epi-F2:4, epi-F2:5).
• Yield benefits diminished by the epi-F2:6 generation, returning to wild-type levels.
• Epigenetic populations showed reduced epitype-by-environment interaction, indicating greater yield stability.
• Differential gene expression in early generations linked to cell cycle, abscisic acid, and auxin pathways (SAURs).

Conclusions:

• The MSH1 system effectively induces stable epigenetic variation in soybean, offering a novel approach for plant breeding.
• MSH1-derived epigenetic variation can enhance seed yield and yield stability, though effects may be transient.
• Understanding the molecular signatures of enhanced growth across generations is crucial for optimizing MSH1-based breeding strategies.