Lopes Cláudia, Fevereiro Pedro, Araújo Susana de Sousa
Plant Cell Biotechnology Laboratory, Green-it Research Unit, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB-NOVA), Oeiras, Portugal.
MORE - Laboratório Colaborativo Montanhas de Investigação, Edificio do Brigantia Ecopark, Bragança, Portugal.
Front Plant Sci. 2025 May 21;16:1597915. doi: 10.3389/fpls.2025.1597915. eCollection 2025.
Common bean ( L.) is one of the most consumed grain legumes. These legumes are a major source of proteins and other important nutrients, especially in developing countries. Studying seed development in common bean is crucial for improving yield, nutrition, stress tolerance and disease resistance while promoting sustainable agriculture and food security, with its sequenced genome and available molecular tools making it an excellent research model. Despite advances in studying seed development, the precise timing and molecular regulation of the transition from embryogenesis to seed filling remain poorly understood. Although seeds at 10 days after anthesis (DAA) were previously characterized as being in the late embryogenesis stage, our previous studies suggested that this transition might occur earlier than 10 DAA, prompting us to investigate earlier developmental stages.
To accomplish this goal, we conducted a comprehensive analysis at 6, 10, 14, 18 and 20 DAA, integrating morphological, histological, and transcriptomic approaches.
Morphological and histochemical data revealed that by 10 DAA, cotyledons are fully formed, but storage compound accumulation is only noticed at 14 DAA, indicating that the transition from embryogenesis to seed filling occurs between 10 and 14 DAA. Transcriptomic analysis further supported this finding, showing upregulation of genes associated with seed storage proteins, starch metabolism, and hormonal regulation at 14 and 18 DAA. This study redefines the developmental timeline of seed filling initiation, bridging a critical knowledge gap in legume seed biology. Given the limited availability of histological studies on early seed development, our findings provide essential insights into the structural and molecular events driving this transition. By refining the timing and regulatory mechanisms of early seed development, this study lays the groundwork for future research aimed at enhancing seed quality and resilience in legumes.
普通菜豆（Phaseolus vulgaris L.）是消费最为广泛的食用豆类之一。这些豆类是蛋白质和其他重要营养素的主要来源，在发展中国家尤为如此。研究普通菜豆的种子发育对于提高产量、营养、抗逆性和抗病性，同时促进可持续农业和粮食安全至关重要，其已测序的基因组和可用的分子工具使其成为一个出色的研究模型。尽管在种子发育研究方面取得了进展，但从胚胎发生到种子充实过渡的精确时间和分子调控仍知之甚少。虽然之前将开花后10天（DAA）的种子表征为处于胚胎发生后期阶段，但我们之前的研究表明，这种过渡可能发生在早于10 DAA的时候，这促使我们对更早的发育阶段进行研究。
为实现这一目标，我们在6、10、14、18和20 DAA时进行了综合分析，整合了形态学、组织学和转录组学方法。
形态学和组织化学数据表明，到10 DAA时，子叶已完全形成，但直到14 DAA才观察到贮藏化合物的积累，这表明从胚胎发生到种子充实的过渡发生在10至14 DAA之间。转录组分析进一步支持了这一发现，显示与种子贮藏蛋白、淀粉代谢和激素调控相关的基因在14和18 DAA时上调。本研究重新定义了种子充实起始的发育时间线，弥合了豆类种子生物学中的一个关键知识空白。鉴于早期种子发育的组织学研究有限，我们的发现为驱动这种过渡的结构和分子事件提供了重要见解。通过完善早期种子发育的时间和调控机制，本研究为未来旨在提高豆类种子质量和抗逆性的研究奠定了基础。
