Wang Xiaoting, He Lufang, Li Jianzhao, Bai Songling, Teng Yuanwen, Hui Wei
Xi'an Botanical Garden of Shaanxi Province, Institute of Botany of Shaanxi Province, Xi'an, China.
College of Life Sciences, Engineering Research Center for High-Valued Utilization of Fruit Resources in Western China of Ministry of Education, Shaanxi Normal University, Xi'an, China.
Front Plant Sci. 2025 Sep 1;16:1667946. doi: 10.3389/fpls.2025.1667946. eCollection 2025.
Plant seeds have evolved diverse dormancy types and regulatory mechanisms to adapt to environmental conditions and seasonal changes. As a commonly used rootstock for cultivated pears, faces challenges in seedling production and large-scale cultivation due to limited understanding of seed dormancy mechanisms. In this study, we report that seeds exhibit non-deep physiological dormancy, with seed coats playing a pivotal regulatory role. Exogenous abscisic acid (ABA) treatment, fluridone application and seed coat bedding assay demonstrated that dormant seed coats actively synthesized ABA to inhibit embryo germination during imbibition. ABA in imbibed dormant seed coats stimulated ABA biosynthesis in embryos, leading to increased expression of genes involved in ABA biosynthesis () and ABA-responsive (, , and ). Importantly, PbeABI5-5 directly binds to the promoters of () to activate their transcription. We establish that in dormant seeds, the seed coat controls embryo dormancy release through coordinated regulation of PbeABI5-GA2ox module, thereby maintaining the critical balance between ABA and GA.
植物种子已经进化出多种休眠类型和调控机制，以适应环境条件和季节变化。作为栽培梨常用的砧木，由于对种子休眠机制了解有限，在幼苗生产和大规模种植方面面临挑战。在本研究中，我们报道了种子表现出非深度生理休眠，种皮起着关键的调控作用。外源脱落酸（ABA）处理、氟啶酮应用和种皮埋片试验表明，休眠种皮在吸胀过程中积极合成ABA以抑制胚萌发。吸胀休眠种皮中的ABA刺激胚中ABA生物合成，导致参与ABA生物合成（）和ABA响应（、、和）的基因表达增加。重要的是，PbeABI5-5直接结合到（）的启动子上以激活其转录。我们确定，在休眠种子中，种皮通过协调调控PbeABI5-GA2ox模块来控制胚休眠的解除，从而维持ABA和GA之间的关键平衡。
