The inositol phospholipid signaling system mediates plant growth, development, and responses to adverse conditions. Diacylglycerol kinase (DGK) is one of the key enzymes in the phosphoinositide-cycle (PI-cycle), which catalyzes the phosphorylation of diacylglycerol (DAG) to form phosphatidic acid (PA). To date, comprehensive genomic and functional analyses of DGKs have not been reported in wheat. In this study, 24 DGK gene family members from the wheat genome (TaDGKs) were identified and analyzed. Each putative protein was found to consist of a DGK catalytic domain and an accessory domain. The analyses of phylogenetic and gene structure analyses revealed that each TaDGK gene could be grouped into clusters I, II, or III. In each phylogenetic subgroup, the TaDGKs demonstrated high conservation of functional domains, for example, of gene structure and amino acid sequences. Four coding sequences were then cloned from Chinese Spring wheat. Expression analysis of these four genes revealed that each had a unique spatial and developmental expression pattern, indicating their functional diversification across wheat growth and development processes. Additionally, TaDGKs were also prominently up-regulated under salt and drought stresses, suggesting their possible roles in dealing with adverse environmental conditions. Further cis-regulatory elements analysis elucidated transcriptional regulation and potential biological functions. These results provide valuable information for understanding the putative functions of DGKs in wheat and support deeper functional analysis of this pivotal gene family. The 24 TaDGKs identified and analyzed in this study provide a strong foundation for further exploration of the biological function and regulatory mechanisms of TaDGKs in response to environmental stimuli.

Background The inositol phospholipid signaling system, which is based on the metabolism of phosphoinositide (PI), mediates plant growth, development, and responses to adversity. Diacylglycerol kinase (DGK) is one of the key enzymes in the PI-cycle, which catalyzes the phosphorylation of diacylglycerol (DAG) to form phosphatidic acid (PA). To date, comprehensive genomic and functional analyses of DGK genes have not been reported in wheat. Results In this study, 20 DGK gene family members from the heterologous hexaploid wheat genome (TaDGKs) were identified and analyzed. Each putative protein was found to consist of a DGK catalytic domain and a accessory domain. The analyses of phylogenetic and gene structure revealed that each TaDGK gene could be grouped to clusters I, II, or III. In each phylogenetic subgroup, the TaDGKs demonstrated high conservation in functional domains, for example gene structure and amino acid sequences. By cloning, four coding sequences were ascertained from Chinese spring wheat. Expression analysis of these four genes revealed that each had a unique spatial and developmental expression pattern, indicating their functional diversification in wheat growth and development processes. Additionally, TaDGKs were also prominently up-regulated express under salt and drought stresses, suggesting their possible roles in dealing with adversity environment. Further cis-regulatory elements analysis elucidated transcriptional regulation and potential biological functions. Conclusions These results provide valuable information for understanding the putative functions of DGK genes in wheat, and conduce to ulterior functional analysis of this pivotal gene family. The 20 TaDGKs identified and analyzed in this study provide a strong foundation for further exploration of the biological function and regulatory mechanisms of TaDGKs in response to environmental stimuli.