Syntenic analysis of <i>GPDH</i> genes from different plant species.

(A) Syntenic analysis of maize, rice, soybean, sorghum and Arabidopsis GPDH genes. (B) Syntenic analysis of maize, rice and sorghum GPDH genes. The chromosomes are depicted as a circle. The colored curves denote the syntenic regions of the GPDH genes.</p

Glycerol-3-phosphate dehydrogenase (GPDH) gene family in <i>Zea mays</i> L.: Identification, subcellular localization, and transcriptional responses to abiotic stresses

<div><p>Glycerol-3-phosphate dehydrogenase (GPDH) catalyzes the formation of glycerol-3-phosphate, and plays an essential role in glycerolipid metabolism and in response to various stresses in different species. In this study, six <i>ZmGPDH</i> genes were obtained by a thorough search against maize genome, and designated as <i>ZmGPDH1-6</i>, respectively. The structural and evolutionary analyses showed that the ZmGPDHs family had typical conserved domains and similar protein structures as the known GPDHs from other plant species. ZmGPDHs were divided into NAD⁺-dependent type A form (ZmGPDH1-5) and FAD-dependent type B form (ZmGPDH6) based on their N-terminal sequences. Four full length ZmGPDHs were fused with GFP fusion proteins, and their subcellular localization was determined. ZmGPDH1 and ZmGPDH3 were located to the cytosol and mainly recruited to the surface of endoplasmic reticulum (ER), whereas ZmGPDH4 and ZmGPDH5 were located in the chloroplast. The transcriptional analysis of the <i>ZmGPDHs</i> in different maize tissues revealed relatively high level of transcripts accumulation of <i>ZmGPDHs</i> in roots and early stage developing seeds. Furthermore, we examined the transcriptional responses of the six <i>GPDH</i> genes in maize under various abiotic stresses, including salt, drought, alkali and cold, and significant induction of <i>ZmGPDH</i>s under osmotic stresses was observed. Together, this work will provide useful information for deciphering the roles of GPDHs in plant development and abiotic stress responses.</p></div

Characteristics of the maize GPDH genes (<i>ZmGPDHs</i>).

<p>Characteristics of the maize GPDH genes (<i>ZmGPDHs</i>).</p

The differential transcript profiling of <i>ZmGPDH</i> genes in different tissues and developmental stages.

<p>(A) The differential transcript accumulation of <i>ZmGPDH</i> genes in maize tissues. The transcripts of <i>ZmGPDHs</i> in subtending leaf was used as a calibrator. (B) The differential transcripts accumulation of <i>ZmGPDHs</i> in developing seeds at 5, 10, 15, 20, 30 and 40 days after flowering (DAF). The transcripts of <i>ZmGPDHs</i> in developing seeds at 40DAF was used as a calibrator. (C) The physiological phenotype in developing seeds at 5, 10, 15, 20, 30 and 40 days after flowering (DAF). The asterisks indicate that the corresponding genes are significantly up or down-regulated in different tissues, as determined by the Student’s <i>t</i>-test (*P < 0.05, ** P < 0.01).</p

Additional file 5: of A cytosolic NAD+-dependent GPDH from maize (ZmGPDH1) is involved in conferring salt and osmotic stress tolerance

Figure S5. Phenotype of ZmGPDH1 OE lines in response to ABA. a The seeds of WT and OE lines were germinated on half-strength MS plates with or without ABA. b Germination rate of WT and OE lines under different concentrations of ABA treatment at day 5 after imbibitions. c 7-day-old WT and OE seedlings were grown on half-strength MS plates without or with ABA for 7 days. d The fresh weigh and primary root length of WT and OE seedlings after ABA treatment. Asterisks indicate significant differences from WT plants by Student′s t-test (*P < 0.05; **P < 0.01). (TIF 10675 kb

Additional file 1: of A cytosolic NAD+-dependent GPDH from maize (ZmGPDH1) is involved in conferring salt and osmotic stress tolerance

Figure S1. Alignment analysis of the ZmGPDH1 and AtGPDHc2 protein sequence (TIF 911 kb

Glycerol-3-phosphate dehydrogenase (GPDH) gene family in <i>Zea mays</i> L.: Identification, subcellular localization, and transcriptional responses to abiotic stresses - Fig 8

<p>The transcript profiling of <i>ZmGPDHs</i> in response to NaCl (A), NaHCO₃ (B), PEG (C), 4°C (D) treatments in leaves of maize seedlings. The transcripts of <i>ZmGPDHs</i> in control environment was used as a calibrator. The asterisks indicate that the corresponding genes were significantly up or down-regulated in response to different treatments, as determined by the Student’s <i>t</i>-test (*P < 0.05, ** P < 0.01).</p

Phylogenetic tree of GPDH proteins from maize (purple triangles), rice (green diamonds), soybean (red circles), sorghum (yellow squares) and <i>Arabidopsis</i> (black circles).

<p>The full-length amino acid sequences of the GPDH proteins were used to construct the phylogenetic tree using the MEGA 5.0. The information of these genes can be seen in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0200357#pone.0200357.s004" target="_blank">S1 Table</a>.</p

The cartoon representation of the predicted 3-dimensional structural models of ZmGPDH1-6.

<p>The 3D structure was generated by homology modeling at the SWISS-MODEL workspace, and the model of <i>Homo sapiens</i> GPD1 (PDB code: 1XOX) and <i>Escherichia coli</i> GlpD (PDB code: 2R46) were used as templates. The a-helices were colored in shocking pink and the β-sheet was shown by yellow arrow.</p

Diagram of the maize GPDH proteins showing the bi-domain structure.

<p>Predicted signal peptides are shown as colored rectangles. The numbered bar indicates the amino acid.</p