RESUMO
MAIN CONCLUSION: Soybean possesses 19 CMF genes which mainly arose from duplication events. Their features and motifs are highly conserved but transcriptional data indicated functional diversity in metabolism and stress responses. CCT [for CONSTANS, CONSTANS-like (CO-like), and timing of CAB expression1 (TOC1)] domain-containing genes play important roles in regulating flowering, plant growth, and grain yield and are also involved in stress responses. The CMF (CCT motif family) genes, included in the CCT family, contain a single CCT domain as the only identifiable domain in their predicted protein sequence and are interesting targets for breeding programs. In this study, we identified 19 putative GmCMF genes, based on the latest soybean (Glycine max) genome annotation. The predicted GmCMF proteins were characterized based on conserved structural features, and a phylogenetic tree was constructed including all CMF proteins from rice and Arabidopsis as representative examples of the monocotyledonous (monocot) and dicotyledonous (dicot) plants, respectively. High similarities in the conserved motifs of the protein sequences and the gene structures were found. In addition, by analyzing the CMF gene family in soybean, we identified seven pairs of genes that originated from segmental chromosomal duplication events attributable to the most recent whole-genome duplication (WGD) event in the Glycine lineage. Expression analysis of GmCMF genes in various tissues and after specific treatments demonstrated tissue and stress-response specific differential expression. Gene expression analysis was complemented by the identification of putative cis-elements present in the promoter regions of the genes through a bioinformatics approach, using the existing soybean reference genome sequence and gene models. Co-functional networks inferred from distinct types of genomics data-including microarrays and RNA-seq samples from soybean-revealed that GmCMF genes might play crucial roles in metabolism and transport processes. The results of this study, the first systematic analysis of the soybean CCT gene family, can serve as a strong foundation for further elucidation of their physiological functions and biological roles.
Assuntos
Genoma de Planta , Glycine max , Proteínas de Plantas , Regulação da Expressão Gênica de Plantas , Genoma de Planta/genética , Família Multigênica , Filogenia , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Glycine max/genética , Glycine max/metabolismoRESUMO
The B-box domain is conserved in a large number of proteins involved in cell growth control, differentiation and transcriptional regulation among animal and plant species. In Arabidopsis thaliana, some works have found that B-box proteins (BBX) play central developmental functions in flowering, light and abiotic stress signaling. Despite the functional importance of this protein family, evolutionary and structural relationships of BBX proteins have not been extensively investigated in the plant kingdom. Using a phylogenetic approach, we conducted a comprehensive evolutionary analysis of the BBX protein family in twelve plant species (four green algae, one moss, one lycophyte, three monocots and three dicots). The analysis classified 214 BBX proteins into five structure groups, which evolved independently at early stages of green plant evolution. We showed that the B-box consensus sequences of each structure groups retained a common and conserved domain topology. Furthermore, we identified seven novel motifs specific to each structure group and a valine-proline (VP) pair conserved at the C-terminus domain in some BBX proteins suggesting that they are required for protein-protein interactions. As it has been documented in mammalian systems, we also found monopartite and bipartite amino acid sequences at the C-terminus domain that could function as nuclear localization signals (NLSs). The five BBX structure groups evolved constrained by the conservation of amino acid sequences in the two B-boxes, but radiating variation into NLSs and novel motifs of each structural group. We suggest that these features are the functional basis for the BBX protein diversity in green plants.