Genome-wide identification, phylogeny and expression analysis of the SPL gene family in wheat

Background Members of the plant-specificSPLgene family (squamosa promoter-binding protein -like) contain the SBP conserved domain and are involved in the regulation of plant growth and development, including the development of plant flowers and plant epidermal hair, the plant stress response, and the synthesis of secondary metabolites. This family has been identified in various plants. However, there is no systematic analysis of theSPLgene family at the genome-wide level of wheat. Results In this study, 56 putativeTaSPLgenes were identified using the comparative genomics method; we renamed themTaSPL001-TaSPL056on their chromosomal distribution. According to the un-rooted neighbor joining phylogenetic tree, gene structure and motif analyses, the 56TaSPLgenes were divided into 8 subgroups. A total of 81TaSPLgene pairs were designated as arising from duplication events and 64 interacting protein branches were identified as involve in the protein interaction network. The expression patterns of 21 randomly selectedTaSPLgenes in different tissues (roots, stems, leaves and inflorescence) and under 4 treatments (abscisic acid, gibberellin, drought and salt) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Conclusions The wheat genome contains 56TaSPLgenes and those in same subfamily share similar gene structure and motifs.TaSPLgene expansion occurred through segmental duplication events. Combining the results of transcriptional and qRT-PCR analyses, most of theseTaSPLgenes were found to regulate inflorescence and spike development. Additionally, we found that 13TaSPLswere upregulated by abscisic acid, indicating thatTaSPLgenes play a positive role in the abscisic acid-mediated pathway of the seedling stage. This study provides comprehensive information on theSPLgene family of wheat and lays a solid foundation for elucidating the biological functions ofTaSPLsand improvement of wheat yield.