Identification and evolution of GRAS transcription factor family in four Brassica species

GRAS transcription factor is a plant-specific transcription factor that plays an important role in various plant processes including plant development and stress responses. Considering this, a comprehensive genome-wide study was conducted to identify the GRAS family in four Brassica crops. The results showed that 48, 35, 92 and 88 GRAS genes were identified from Brassica rapa, Brassica oleracea, Brassica napus, and Brassica juncea, respectively. Phylogenetic analysis divided these GRAS gene family members into 9 subgroups. Chromosome localization revealed that GRAS genes are widely distributed on chromosomes. Homologous gene pairs are widely existed in four species, indicating that GRAS transcription factors had common ancestors in Brassica species and were involved in genome doubling in Brassica species differentiation. These studies provide important theoretical basis for revealing the function of GRAS gene in Brassica.