Buckwheat FeAUR3 enhances drought tolerance via a melatonin feedback loop.

Area of Science:

• Plant Biology
• Molecular Biology
• Stress Physiology

Background:

• Aurora kinases regulate cell division but their role in plant abiotic stress is unknown.
• Melatonin protects against drought, but its biosynthesis regulation under stress needs clarification.
• Understanding these pathways is crucial for engineering drought-tolerant crops.

Purpose of the Study:

• Identify upstream regulators of melatonin biosynthesis in plants under drought stress.
• Investigate the role of buckwheat Aurora kinase FeAUR3 in drought tolerance.
• Elucidate the regulatory mechanism of FeAUR3 in plant drought adaptation.

Main Methods:

• Gene expression analysis in transgenic Arabidopsis and buckwheat hairy roots.
• Biochemical assays for antioxidant enzyme activities (SOD, POD) and H2O2 content.
• Proline content measurement.
• Molecular docking and dynamics simulations.
• Analysis of melatonin biosynthesis gene expression (FeAANAT, FeHIOMT).

Main Results:

• FeAUR3 overexpression enhanced antioxidant capacity, proline accumulation, and reduced H2O2 in transgenic plants.
• FeAUR3 directly upregulated melatonin biosynthesis genes, increasing endogenous melatonin levels.
• Melatonin positively regulated FeAUR3 expression, forming a feedback loop.
• Melatonin showed high-affinity binding to FeAUR3.

Conclusions:

• FeAUR3 is a critical upstream regulator of melatonin-mediated drought response.
• A FeAUR3-melatonin module orchestrates drought adaptation through a positive feedback loop.
• FeAUR3 is a promising target for developing drought-resilient crops.