Genome-wide bioinformatics analysis reveals the evolutionary origin of BnGRAS genes in the Brassica genus

As important plant-specific transcription factors, GRAS family members play significant roles in plant development and diverse stress responses. The identification of GRAS genes in many species has been explored; however, little is known about the evolutionary origin of GRAS genes of Brassica napus (BnGRAS genes or BnGRASs)Brassica napus (BnGRAS genes or BnGRASs) in the Brassica genus. Here, 56, 53 and 96 GRAS genes were identified in Brassica rapa, Brassica oleracea, and B. napus, respectively, which were classified into 13 subfamilies and 17 orthologous groups by phylogenetic analysis. Duplication analysis showed that the Brassica-alpha whole genome triplication event contributed more to the expansion of BnGRAS genes than allopolyploidization and tandem duplication. Moreover, all Brassica GRAS genes were estimated to have undergone purifying selection during their evolution. Additionally, structural feature and expression profile analyses indicated that GRAS genes were conserved in sequence characters within the same subfamily, suggesting similar functions in plant development and biotic and abiotic stress responses. Finally, the evolutionary origin of BnGRASs in the Brassica genus was proposed. Taken together, this study not only deduces the evolutionary origin of BnGRASs in the Brassica genus but also provides important candidate BnGRAS genes for further functional analysis.

Automated summary

As important transcription factors, GRAS family members are crucial for plant development and stress responses. This study provides insights into the evolutionary origin and conservation of GRAS genes in the Brassica genus. The findings highlight the role of gene duplication and purifying selection in the expansion and maintenance of GRAS genes, and suggest their conserved functions in plant development and stress responses.