Background: Formin proteins are crucial regulators of actin filament assembly and elongation in eukaryotic cells, playing important roles in plant development and abiotic stress responses. However, the functional characterization of formins in Brassica rapa remains uncover. Methods: A total of 27 formin family members (BrFHs) were identified through genome-wide alignment with Arabidopsis thaliana. Results: Phylogenetic analysis classified BrFH gene family into two distinct clades, designated Group I and Group II, which exhibit divergent protein architectures. Promoter analysis revealed that BrFHs contain multiple cis-regulatory elements related to growth and development, stress responses, and phytohormone signaling. These findings suggest that BrFHs may have diversified functions. Tissue-specific expression analysis revealed that BrFHs exhibit distinct expression patterns across various tissues. Notably, BrFH15 and BrFH18 are highly expressed in flowers, displaying expression profiles similar to those of floral development genes such as AP3, AGL10 and so on. Additionally, many BrFHs show dynamic expression patterns in response to cold stresses. In particular, BrFH2, BrFH19 and BrFH27 were up-regulated, and their co-expression within the gene network suggests potential roles in regulating cold stress. Conclusions: These results clarify the functional roles of BrFHs and shed light on the molecular mechanisms underlying their regulation of tissue development and responses to abiotic stress in Brassica rapa.

Background: Formin proteins are crucial regulators of actin filament assembly and elongation in eukaryotic cells, playing important roles in plant development and abiotic stress responses. However, the functional characterization of formins in Brassica rapa L. remains undiscovered. Methods: A total of 27 formin family members (BrFHs) were identified through genome-wide alignment with Arabidopsis thaliana (L.) Heynh. Results: Phylogenetic analysis classified BrFH gene family into two distinct clades, designated Group I and Group II, which exhibit divergent protein architectures. Promoter analysis revealed that BrFHs contain multiple cis-regulatory elements related to growth and development, stress responses, and phytohormone signaling. These findings suggest that BrFHs may have diversified functions. Tissue-specific expression analysis revealed that BrFHs exhibit distinct expression patterns across various tissues. Notably, BrFH15 and BrFH18 are highly expressed in flowers, displaying expression profiles similar to those of floral development genes such as AP3, AGL10 and so on. Additionally, many BrFHs show dynamic expression patterns in response to cold stresses. In particular, BrFH2, BrFH19 and BrFH27 were up-regulated, and their co-expression within the gene network suggests potential roles in regulating cold stress. Conclusions: These results clarify the functional roles of BrFHs and shed light on the molecular mechanisms underlying their regulation of tissue development and responses to cold stress in Brassica rapa.