Citrus FRIGIDA cooperates with its interaction partner dehydrin to regulate drought tolerance

Area of Science:

• Plant Biology
• Molecular Genetics
• Agricultural Science

Background:

• Drought stress significantly impacts plant growth and crop yields globally.
• FRIGIDA (FRI) is a known regulator of flowering time and drought tolerance in model plants.
• The function of FRI orthologs in woody plants, such as citrus, remains largely unexplored.

Purpose of the Study:

• To investigate the functional role of the citrus FRI ortholog (CiFRI) in drought stress response.
• To elucidate the molecular mechanisms underlying CiFRI-mediated drought tolerance in citrus.
• To identify upstream regulators of CiFRI in citrus under drought conditions.

Main Methods:

• Drought stress treatments applied to transgenic Arabidopsis and citrus plants.
• Gene expression analysis, including transcriptomic profiling under drought.
• Biochemical assays to investigate protein interactions and promoter binding.

Main Results:

• Drought stress induced CiFRI expression in citrus.
• Overexpression of CiFRI enhanced drought tolerance in both Arabidopsis and citrus.
• Suppression of CiFRI increased drought susceptibility in citrus.
• Transcriptomic analysis revealed CiFRI regulates stress response, hormone biosynthesis, and signaling pathways.
• Citrus dehydrin protects CiFRI from degradation, and CiBZR1 directly activates CiFRI expression under drought.
• CiBZR1 also conferred drought tolerance in transgenic plants.

Conclusions:

• CiFRI plays a crucial role in mediating drought tolerance in citrus.
• The CiFRI-CiBZR1 regulatory module is essential for citrus drought stress response.
• Understanding these mechanisms can aid in developing drought-resilient citrus varieties.