Diacylglycerol Kinases Are Widespread in Higher Plants and Display Inducible Gene Expression in Response to Beneficial Elements, Metal, and Metalloid Ions

Abstract

Diacylglycerol kinases (DGKs) are pivotal signaling enzymes that phosphorylate diacylglycerol (DAG) to yield phosphatidic acid (PA). The biosynthesis of PA from phospholipase D (PLD) and the coupled phospholipase C (PLC)/DGK route is a crucial signaling process in eukaryotic cells. Next to PLD, the PLC/DGK pathway is the second most important generator of PA in response to biotic and abiotic stresses. In eukaryotic cells, DGK, DAG, and PA are implicated in vital processes such as growth, development, and responses to environmental cues. A plethora of DGK isoforms have been identified so far, making this a rather large family of enzymes in plants. Herein we performed a comprehensive phylogenetic analysis of DGK isoforms in model and crop plants in order to gain insight into the evolution of higher plant DGKs. Furthermore, we explored the expression profiling data available in public data bases concerning the regulation of plant DGK genes in response to beneficial elements and other metal and metalloid ions, including silver (Ag), aluminum (Al), arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and sodium (Na). In all plant genomes explored, we were able to find DGK representatives, though in different numbers. The phylogenetic analysis revealed that these enzymes fall into three major clusters, whose distribution depends on the composition of structural domains. The catalytic domain conserves the consensus sequence GXGXXG/A where ATP binds. The expression profiling data demonstrated that DGK genes are rapidly but transiently regulated in response to certain concentrations and time exposures of beneficial elements and other ions in different plant tissues analyzed, suggesting that DGKs may mediate signals triggered by these elements. Though this evidence is conclusive, further signaling cascades that such elements may stimulate during hormesis, involving the phosphoinositide signaling pathway and DGK genes and enzymes, remain to be elucidated.

Mapping of quantitative trait loci for grain yield and its components in a US popular winter wheat TAM 111 using 90K SNPs

“…2 is within TRIAE_CS42_6AL_TGACv1_472318_AA1520780 gene on the long arm of chromosome 6A ( http://plants.ensembl.org ). The gene has four transcripts and codes Diacylglycerol kinase which play a role in signaling under biotic and abiotic stress [ 35 ]. Another peak marker, IWB67907, is within a predicted TRIAE_CS42_6AL_TGACv1_472781_AA1525920 gene that codes Alphamannosidase.…”

Genomic profiling and expression analysis of the diacylglycerol kinase gene family in heterologous hexaploid wheat

“…In addition, all three ZmDGKs, six of the eight DGKs in the apple genome, and almost all GmDGKs had signi cantly induced expression under PEG or salt treatments [9][10]13]. Although the functional identi cation of plant DGKs is still unthorough, these ndings con rmed the role of DGK in osmotic stress, and it was bene t of researching onthe relationship between the paired PLC/DGK pathway and environmental stresses in plant responses [33].…”

Genome-wide identification and comparative analysis of diacylglycerol kinase (DGK) gene family and their expression profiling in Brassica napus under abiotic stress

“…A previous study reported that DGK genes in land plants can respond to known beneficial elements as well as to other metal and metalloid ions [18]. We conducted BnaDGK expression profiling based on RNA-seq data from B. napus cultivars subjected to heavy metal induction (Additional file 7: Fig.…”

“…In B. napus roots, exogenous application of 24-epibrassinolide (EBL) affects PA synthesis through the PLC/DGK pathway under optimal salinity conditions [17]. Furthermore, DGK genes are rapidly but transiently regulated in different plant tissues in response to beneficial elements and other ions, including silver (Ag), aluminum (Al), arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and sodium (Na) [18]. Notably, DGK genes may be candidates for influencing seed oil content in B. napus, according to recent unpublished data from our laboratory.…”