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Wheat (Triticum aestivum L.) is one of the oldest cultivated crops and the second most important food crop in the world. Seed germination is the key developmental process in plant growth and development, and poor germination directly affects plant growth and subsequent grain yield. In this study, we performed the first dynamic proteome analysis of wheat seed germination using a two-dimensional differential gel electrophoresis (2D-DIGE)-based proteomic approach. A total of 166 differentially expressed protein (DEP) spots representing 73 unique proteins were identified, which are mainly involved in storage, stress/defense/detoxification, carbohydrate metabolism, photosynthesis, cell metabolism, and transcription/translation/transposition. The identified DEPs and their dynamic expression profiles generally correspond to three distinct seed germination phases after imbibition: storage degradation, physiological processes/morphogenesis, and photosynthesis. Some key DEPs involved in storage substance degradation and plant defense mechanisms, such as globulin 3, sucrose synthase type I, serpin, beta-amylase, and plastid ADP-glucose pyrophosphorylase (AGPase) small subunit, were found to be phosphorylated during seed germination. Particularly, the phosphorylation site Ser355 was found to be located in the enzyme active region of beta-amylase, which promotes substrate binding. Phosphorylated modification of several proteins could promote storage substance degradation and environmental stress defense during seed germination. The central metabolic pathways involved in wheat seed germination are proposed herein, providing new insights into the molecular mechanisms of cereal seed germination.

BackgroundWheat seeds provide a staple food and an important protein source for the world’s population. Seed germination is vital to wheat growth and development and directly affects grain yield and quality. In this study, we performed the first comparative proteomic analysis of wheat embryo and endosperm during seed germination.ResultsThe proteomic changes in embryo and endosperm during the four different seed germination stages of elite Chinese bread wheat cultivar Zhengmai 9023 were first investigated. In total, 74 and 34 differentially expressed protein (DEP) spots representing 63 and 26 unique proteins were identified in embryo and endosperm, respectively. Eight common DEP were present in both tissues, and 55 and 18 DEP were specific to embryo and endosperm, respectively. These identified DEP spots could be sorted into 13 functional groups, in which the main group was involved in different metabolism pathways, particularly in the reserves necessary for mobilization in preparation for seed germination. The DEPs from the embryo were mainly related to carbohydrate metabolism, proteometabolism, amino acid metabolism, nucleic acid metabolism, and stress-related proteins, whereas those from the endosperm were mainly involved in protein storage, carbohydrate metabolism, inhibitors, stress response, and protein synthesis. During seed germination, both embryo and endosperm had a basic pattern of oxygen consumption, so the proteins related to respiration and energy metabolism were up-regulated or down-regulated along with respiration of wheat seeds. When germination was complete, most storage proteins from the endosperm began to be mobilized, but only a small amount was degraded during germination. Transcription expression of six representative DEP genes at the mRNA level was consistent with their protein expression changes.ConclusionWheat seed germination is a complex process with imbibition, stirring, and germination stages, which involve a series of physiological, morphological, and proteomic changes. The first process is a rapid water uptake, in which the seed coat becomes softer and the physical state of storage materials change gradually. Then the germinated seed enters the second process (a plateau phase) and the third process (the embryonic axes elongation). Seed embryo and endosperm display distinct differentially expressed proteins, and their synergistic expression mechanisms provide a basis for the normal germination of wheat seeds.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0471-z) contains supplementary material, which is available to authorized users.

Postsurgical gastroparesis syndrome (PGS) is a complex disorder characterized by post-prandial nausea and vomiting, and gastric atony in the absence of mechanical gastric outlet obstruction, and is often caused by operation at the upper abdomen, especially by gastric or pancreatic resection, and sometimes also by operation at the lower abdomen, such as gynecological or obstetrical procedures. PGS occurs easily with oral intake of food or change in the form of food after operation. These symptoms can be disabling and often fail to be alleviated by drug therapy, and gastric reoperations usually prove unsuccessful. The cause of PGS has not been identified, nor has its mechanism quite been clarified. PGS after gastrectomy has been reported in many previous studies, with an incidence of approximately 0.4-5.0%. PGS is also a frequent complication of pylorus-preserving pancreatoduodenectomy (PPPD), and the complication occurs in the early postoperative period in 20-50% of patients. PGS caused by pancreatic cancer cryoablation (PCC) has been reported about in 50-70% of patients. Therefore, PGS has a complex etiology and might be caused by multiple factors and mechanisms. The frequency of this complication varies directly with the type and number of gastric operations performed. The loss of gastric parasympathetic control resulting from vagotomy contributes to PGS via several mechanisms. It has been reported that the interstitial cells of Cajal (ICC) may play a role in the pathogenesis of PGS. Recent studies in animal models of diabetes suggest specific molecular changes in the enteric nervous system may result in delayed gastric emptying. The absence of the duodenum, and hence gastric phase III, may be a cause of gastric stasis. It was thought that PGS after PPPD might be attributable, at least in part, to delayed recovery of gastric phase III, due to lowered concentrations of plasma motilin after resection of the duodenum. The damage to ICC might play a role in the pathogenesis of PGS after PCC, for which multiple factors are possibly responsible, including ischemic and neural injury to the antropyloric muscle and the duodenum after freezing of the pancreatoduodenal regions or reduction of circulating levels of motilin. As the treatment of gastroparesis is far from ideal, non-conventional approaches and non-standard medications might be of use. Multiple treatments are better than single treatment. This article reviews almost all the papers related to PGS from various journals published in English and Chinese in recent years in order to facilitate a better understanding of PGS.

The drought-tolerant ‘Ningchun 47’ (NC47) and drought-sensitive ‘Chinese Spring’ (CS) wheat (Triticum aestivum L.) cultivars were treated with different PEG6000 concentrations at the three-leaf stage. An analysis on the physiological and proteomic changes of wheat seedling in response to drought stress was performed. In total, 146 differentially accumulated protein (DAP) spots were separated and recognised using two-dimensional gel electrophoresis. In total, 101 DAP spots representing 77 unique proteins were identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. These proteins were allocated to 10 groups according to putative functions, which were mainly involved in carbon metabolism (23.4%), photosynthesis/respiration (22.1%) and stress/defence/detoxification (18.2%). Some drought stress-related proteins in NC47, such as enolase, 6-phosphogluconate dehydrogenase, Oxygen-evolving enhancer protein 2, fibrillin-like protein, 2-Cys peroxiredoxin BAS1 and 70-kDa heat shock protein, were more upregulated than those in CS. Multivariate principal components analysis revealed obvious differences between the control and treatments in both NC47 and CS, while cluster analysis showed that the DAPs displayed five and six accumulation patterns in NC47 and CS, respectively. Protein–protein interaction network analysis showed that some key DAPs, such as 2-Cys peroxiredoxin BAS1, RuBisCO large subunit-binding protein, 50S ribosomal protein L1, 6-phosphogluconate dehydrogenase, glyceraldehyde 3-phosphate dehydrogenase isoenzyme and 70-kDa heat shock protein, with upregulated accumulation in NC47, had complex interactions with other proteins related to amino acid metabolism, carbon metabolism, energy pathway, signal transduction, stress/defence/detoxification, protein folding and nucleotide metabolism. These proteins could play important roles in drought-stress tolerance and contribute to the relatively stronger drought tolerance of NC47.