Genome-Wide Identification of the FWL Gene Family in Rice Reveals Critical Roles in Abiotic Stress Response

Area of Science:

• Plant Molecular Biology
• Genomics
• Stress Physiology

Background:

• The Fruit Weight 2.2-like (FWL) gene family, defined by the PLAC8 domain, is vital for plant organ development and metal ion balance.
• Systematic characterization of rice FWL genes and their role in abiotic stress responses is limited.

Purpose of the Study:

• To conduct a genome-wide identification and characterization of the FWL gene family in rice (Oryza sativa).
• To investigate the involvement of rice FWL genes in response to various abiotic stresses.
• To functionally characterize OsFWL8 in arsenic stress tolerance.

Main Methods:

• Genome-wide identification of FWL genes in rice.
• Phylogenetic, structural, motif, and promoter analyses of OsFWL genes.
• Expression profiling under drought, high temperature, salt, and arsenic stresses.
• Functional analysis using CRISPR/Cas9 knockout and overexpression lines for OsFWL8.

Main Results:

• Nine OsFWL genes were identified, including a novel member, OsFWL9.
• Phylogenetic analysis revealed three distinct subgroups within the FWL family across multiple species.
• Most OsFWL genes were induced by various abiotic stresses, with OsFWL8 showing unique suppression under arsenic stress.
• OsFWL8 was confirmed to negatively regulate arsenic tolerance, with its mutants showing enhanced tolerance and altered expression of detoxification genes.

Conclusions:

• The rice FWL gene family comprises nine members with conserved structures and stress-responsive cis-acting elements.
• OsFWL8 plays a critical role in negatively regulating arsenic tolerance in rice, potentially by modulating arsenic sequestration and detoxification.
• This study provides valuable insights for enhancing rice tolerance to heavy metal stress through genetic manipulation of OsFWL8.