A functionally divergent SOC1 homolog improves soybean yield and latitudinal adaptation

Area of Science:

• Plant genetics
• Molecular biology
• Agricultural science

Background:

• Soybean (Glycine max) is sensitive to photoperiod, limiting its adaptation and yield across latitudes.
• Understanding the genetic basis of soybean adaptation is crucial for crop improvement and breeding programs.

Purpose of the Study:

• To characterize Tof18 (SOC1a) and its role in soybean flowering time, growth habit, and latitudinal adaptation.
• To investigate the functional divergence between soybean SOC1 homologs (SOC1a and SOC1b).

Main Methods:

• Molecular characterization of Tof18 (SOC1a) and its homolog SOC1b.
• Analysis of single and double mutants (soc1a soc1b).
• Investigating the interaction of SOC1s with FTs and the Dt1 gene.

Main Results:

• Tof18 (SOC1a) significantly affects flowering time and stem node number, with greater impact than SOC1b due to transcriptional differences.
• Double mutants (soc1a soc1b) exhibited stronger effects, suggesting potential homodimer or heterodimer formation.
• The Tof18^G allele enhances high-latitude adaptation, while the Tof18^A allele facilitates low-latitude adaptation.
• SOC1s regulate floral induction with FTs and, along with SOC1b and Dt2, directly bind to Dt1 regulatory sequences, controlling stem growth habit.

Conclusions:

• SOC1a plays a vital role in soybean's latitudinal adaptation and yield potential.
• The Tof18^A allele, which increases node number, offers a valuable target for genetic improvement of soybean cultivars.
• Genome editing of SOC1 genes presents a promising strategy for enhancing soybean yield and optimizing land use for global food security.