FLL2 modulates Arabidopsis development and stress tolerance via polyadenylation and CPSF73 interaction

Area of Science:

• Plant Molecular Biology
• Gene Regulation
• Biochemistry

Background:

• The coiled-coil protein FLL2 is implicated in liquid-liquid phase separation within the polyadenylation complex.
• The precise role of FLL2 in the polyadenylation process and its broader biological functions remain largely uncharacterized.

Purpose of the Study:

• To investigate the function of FLL2 in Arabidopsis, particularly its role in polyadenylation and its relationship with CPSF73.
• To elucidate how FLL2 impacts plant development, stress tolerance, and gene expression regulation.

Main Methods:

• Utilized a developmental mutant sof78 in the Arabidopsis FLL2 gene.
• Employed the benzoxaborole compound AN3661, a known inhibitor of CPSF73, to probe FLL2-CPSF73 interactions.
• Applied poly(A) tag sequencing (PAT-seq) to analyze alternative polyadenylation (APA) events across the transcriptome.

Main Results:

• The sof78 mutant exhibited developmental alterations and altered oxidative stress tolerance.
• Treatment with AN3661 mimicked some mutant phenotypes, suggesting co-regulation by CPSF73 and FLL2.
• PAT-seq revealed significant changes in APA events in the sof78 mutant under AN3661 treatment or oxidative stress, with altered poly(A) signal composition and shifts in canonical/non-canonical site usage.
• Affected genes were enriched in pathways related to abiotic stress, hormone signaling (auxin, ethylene), and osmotic stress.

Conclusions:

• FLL2 and CPSF73 co-modulate plant growth, development, and adaptation through the regulation of alternative polyadenylation.
• APA mediated by FLL2 and CPSF73 plays a critical role in plant responses to environmental stimuli and developmental processes.