Integrative Mechanisms of Sucrose and Gibberellin in Regulating Soybean Flowering

As a pivotal global oil crop, soybean production plays a vital role in ensuring food security and promoting sustainable development. The processes of flowering and pod drop are critical determinants of soybean yield, thus, effective regulation of flowering is essential for achieving both high and stable yields. The differentiation of flower buds marks a crucial stage in the flowering process, governed by a complex interplay of environmental and endogenous pathways, including photoperiodic, vernalization, autonomous, gibberellin, and age pathways. These pathways converge to integrate flowering signals, subsequently activating downstream floral meristem identity genes that orchestrate the formation of floral primordia. Sucrose, the primary sugar transport form in soybeans, serves not only as a fundamental component of carbon metabolism but also as a significant signaling molecule. Through the age pathway, sucrose harmonizes various flowering-related genes, thereby influencing the timing of soybean flowering. Gibberellin, an essential hormone for plant growth and development, modulates flowering through the gibberellin pathway, with DELLA proteins acting as key regulators in the signal transduction cascade. The synergistic interaction between sucrose and gibberellin on gene expression occurs via distinct signaling pathways, collectively orchestrating flower bud differentiation. A thorough exploration of the molecular mechanisms by which sugars and hormones regulate flowering is anticipated to yield valuable insights and guidance for enhancing field crop production. This study highlights the critical role of soybean (Glycine max) as a global oil crop, emphasizing its importance in food security and sustainable agricultural development. Our findings reveal that the processes of flowering and pod drop are pivotal determinants of soybean yield, underscoring the necessity for effective regulation of flowering to achieve both high and stable yields. We identified that flower bud differentiation is a crucial phase in the flowering process, regulated by a complex interplay of environmental and endogenous pathways, including photoperiodic, vernalization, autonomous, gibberellin, and age pathways. These pathways work in concert to integrate flowering signals, which subsequently activate downstream floral meristem identity genes responsible for the formation of floral primordia. Our research further elucidates the dual role of sucrose, the primary form of sugar transport in soybeans, as both a fundamental component of carbon metabolism and a significant signaling molecule. Through the age pathway, sucrose coordinates the expression of various flowering-related genes, thereby influencing the timing of flowering in soybeans. Additionally, we found that gibberellin, a vital hormone for plant growth and development, regulates flowering through its specific signaling pathway, with DELLA proteins serving as key regulators in the signal transduction process. The synergistic effects of sucrose and gibberellin on gene expression occur through distinct signaling pathways, collectively orchestrating the differentiation of flower buds. Overall, our comprehensive exploration of the molecular mechanisms by which sugars and hormones regulate flowering in soybeans is expected to provide valuable insights and practical guidance for enhancing field crop production, ultimately contributing to improved agricultural practices and food security.