Buckwheat FeAUR3 enhances drought tolerance via a melatonin feedback loop

作者：Zhanyu Wang, Luping Ma, Chunyun Zhou, Mengyu Zhao, Jia Yao Yang, Yongzhi Qi, Zemiao Tian, Lixia Cao, Muriel Quinet, Yu Meng, Jiadong He · 发表于：Plant Physiology and Biochemistry · 年份：2026 · DOI：10.1016/j.plaphy.2026.111151 · 被引用次数：1 · 研究领域：Circadian rhythm and melatonin、Plant Molecular Biology Research、Light effects on plants

Aurora kinases are pivotal regulators of cell division, yet their roles in plant abiotic stress responses remain largely unexplored. While melatonin is a well-established protectant against drought, the upstream genetic pathways governing its biosynthesis under stress are not fully understood, limiting our ability to engineer robust drought tolerance. Here, we identify the buckwheat Aurora kinase, FeAUR3, as a critical upstream regulator of the melatonin-mediated drought response. In transgenic Arabidopsis , overexpression lines exhibited a marked enhancement in antioxidant capacity, with superoxide dismutase (SOD) and peroxidase (POD) activities increasing by up to 3.75-fold and 3.35-fold, respectively, alongside a 66.14% increase in proline accumulation and a 37.50% reduction in H 2 O 2 content. Similarly, in buckwheat hairy roots, FeAUR3 overexpression strongly activated the antioxidant system, elevating SOD activity by up to 7.50-fold. Mechanistically, the nucleus-localized FeAUR3 directly upregulates the expression of melatonin biosynthesis genes FeAANAT and FeHIOMT , leading to a 23.6% elevation in endogenous melatonin levels, which initiates a coordinated defense response. Furthermore, we discovered that melatonin acts as an upstream positive regulator, further inducing FeAUR3 expression (by 1.12-fold under drought) to form a positive feedback loop that amplifies stress signaling. Molecular docking and dynamics simulations confirmed that melatonin stably binds to FeAUR...