Genome-wide identification and characterization of GRAS genes in soybean (Glycine max)

Background GRAS proteins are crucial transcription factors, which are plant-specific and participate in various plant biological processes. Thanks to the rapid progress of the whole genome sequencing technologies, theGRASgene families in different plants have been broadly explored and studied. However, comprehensive research on the soybean (Glycine max)GRASgene family is relatively lagging. Results In this study, 117Glycine maxGRASgenes (GmGRAS) were identified. Further phylogenetic analyses showed that theGmGRASgenes could be categorized into nine gene subfamilies: DELLA, HAM, LAS, LISCL, PAT1, SCL3, SCL4/7, SCR and SHR. Gene structure analyses turned out that theGmGRASgenes lacked introns and were relatively conserved. Conserved domains and motif patterns of theGmGRASmembers in the same subfamily or clade exhibited similarities. Notably, the expansion of theGmGRASgene family was driven both by gene tandem and segmental duplication events. Whereas, segmental duplications took the major role in generating newGmGRASgenes. Moreover, the synteny and evolutionary constraints analyses of the GRAS proteins among soybean and distinct species (two monocots and four dicots) provided more detailed evidence forGmGRASgene evolution.Cis-element analyses indicated that theGmGRASgenes may be responsive to diverse environmental stresses and regulate distinct biological processes. Besides, the expression patterns of theGmGRASgenes were varied in various tissues, during saline and dehydration stresses and during seed germination processes. Conclusions We conducted a systematic investigation of theGRASgenes in soybean, which may be valuable in paving the way for futureGmGRASgene studies and soybean breeding.