The transcription factor family in soybean: Genome-wide identification, expression profiling and genetic diversity analysis.

The transcription factor family plays a critical role in the ethylene signaling pathway, which regulates a broad spectrum of plant growth and developmental processes, as well as defenses to myriad stresses. Although genome-wide analysis of this family has been carried out for several plant species, no comprehensive analysis of the gene family in soybean has been reported so far. Furthermore, there are few studies on the functions of genes in soybean. In this study, we identified 12 soybean () genes, which we divided into three groups based on their phylogenetic relationships. We then detected their duplication status and found that most of the genes have duplicated copies derived from two whole-genome duplication events. These duplicated genes underwent strong negative selection during evolution. We further analyzed the transcript profiles of genes using the transcriptome data and found that their spatio-temporal and stress expression patterns varied considerably. For example, - were found to be strongly expressed in almost every sample, while - exhibited low expression, or were not expressed at all. Additionally, these genes showed different responses to dehydration, salinity and phosphate starvation. Finally, we surveyed genetic variations of these genes in 302 resequenced wild soybeans, landraces and improved soybean cultivars. Our data showed that most genes are well conserved, and are not modified in domesticated or improved cultivars. Together, these findings provide a potentially valuable resource for characterizing the gene family and lay the basis for further elucidation of their molecular mechanisms.