Genome-wide characterization and expression pattern of auxin response factor (ARF) gene family in soybean and common bean

Auxin response factors (ARFs) encode one of the most abundant groups of auxin-mediated response transcription factors in higher plants and play a major role in various biological processes. The success of whole genome sequencing allows for comprehensive phylogenetic analysis of ARF genes in plants. Here, we identified 80 ARF genes belonging to five different groups in legume species, soybean (Glycine max, 55) and common bean (Phaseolus vulgaris, 25), based on phylogenetic analysis and supported by motif analysis. There is no member ARF of common bean in group V which contained two members from soybean, GmARF12 and GmARF55. The duplication events among two species were also observed by using Ks values. A majority of the ARF genes (96.1 %; 38 GmARFs and 56.0 %, 14 PvARFs) were segmentally duplicated while only two and one of ARF G. max and P. vulgaris genes were tandemly duplicated, respectively. In addition, expression profiling indicated that ARF genes in soybean and common bean perform various functions in plant growth and development, excluding flowering development. Furthermore, diversity of cis-elements in promoter regions also revealed differential expression of ARF proteins.