Genome wide identification and expression pattern analysis of the GRAS family in quinoa

GRAS, a key transcription factor in plant growth and development, has not yet been reported in quinoa. Therefore, this study used the latest quinoa genomic data to identify and analyse GRAS genes in quinoa: 52 GRAS genes were identified in quinoa, these being unevenly distributed on 19 chromosomes. Fragment duplication and tandem duplication events were the main reasons for the expansion of the GRAS gene family in quinoa. Protein sequence analysis showed that there were some differences in amino acid numbers and isoelectric points amongst different subfamilies, and the main secondary structures were α-helix and random coil. The CqGRAS gene was divided into 14 subfamilies based on results from phylogenetic analysis. The genes located in the same subfamily had similar gene structures, conserved motifs, and three-level models. Promoter region analysis showed that the GRAS family genes contained multiple homeostasis elements that responded to hormones and adversity. GO enrichment indicated that CqGRAS genes were involved in biological processes, cell components, and molecular functions. By analysing the expression of CqGRAS genes in different tissues and different treatments, it was found that GRAS genes had obvious differential expression in different tissues and stress, which indicates that GRAS genes had tissue or organ expression specificity and thus might play an important role in response to stress. These results laid a foundation for further functional research on the GRAS gene family in quinoa.