Wild barley germplasms are a treasure trove of useful genes and provide rich sources of genetic variation for crop improvement. We carried out a hydroponic and pot evaluation of diverse germplasms in response to drought stress using 47 Tibet annual wild barley genotypes. Our results from the hydroponic experiment showed that SPAD (soilplant analyses development analyses, based on chlorophyll meter readings), plant height, and biomass of shoot/root were significantly reduced in plants exposed to drought stress (exposure of plant roots to air for 6 h daily for a period of 7 days) compared with control plants. There were significant differences among the 47 wild barley genotypes in terms of the reduction in these growth parameters, with variation coefficients and diversity indexes ranging from 23.2 to 49.1% and 1.46 to 1.62, respectively, suggesting a rich genetic diversity among the tested accessions. Genotypes XZ5 and XZ150 showed the least reduction, indicating their high tolerance to drought stress, while genotypes XZ54 and XZ147 showed the greatest reduction, and drought stress symptoms appeared rapidly and severely in these latter genotypes. The trends in the different responses of these genotypes to drought stress were fairly consistent in both the hydroponic and the two pot selection experiments, with XZ5 and XZ150 screened as drought-resistant genotypes and XZ54, XZ147 as drought-sensitive ones. Significant genotypic differences in leaf soluble sugar content and water use efficiency in response to drought stress were also observed in pot experiment two, with the droughttolerant genotype XZ5 showing a markedly higher recovery and the two drought-sensitive genotypes XZ54 and XZ147 showing a markedly lower recovery than the control plants.

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BackgroundDrought is one of major abiotic stresses constraining crop productivity worldwide. To adapt to drought stress, plants have evolved sophisticated defence mechanisms. Wild barley germplasm is a treasure trove of useful genes and offers rich sources of genetic variation for crop improvement. In this study, a proteome analysis was performed to identify the genetic resources and to understand the mechanisms of drought tolerance in plants that could result in high levels of tolerance to drought stress.ResultsA greenhouse pot experiment was performed to compare proteomic characteristics of two contrasting Tibetan wild barley genotypes (drought-tolerant XZ5 and drought-sensitive XZ54) and cv. ZAU3, in response to drought stress at soil moisture content 10 % (SMC10) and 4 % (SMC4) and subsequently 2 days (R1) and 5 days (R2) of recovery. More than 1700 protein spots were identified that are involved in each gel, wherein 132, 92, 86, 242 spots in XZ5 and 261, 137, 156, 187 in XZ54 from SMC10, SMC4, R1 and R2 samples were differentially expressed by drought over the control, respectively. Thirty-eight drought-tolerance-associated proteins were identified using mass spectrometry and data bank analysis. These proteins were categorized mainly into photosynthesis, stress response, metabolic process, energy and amino-acid biosynthesis. Among them, 6 protein spots were exclusively expressed or up-regulated under drought stress in XZ5 but not in XZ54, including melanoma-associated antigen p97, type I chlorophyll a/b-binding protein b, glutathione S-transferase 1, ribulosebisphosphate carboxylase large chain. Moreover, type I chlorophyll a/b-binding protein b was specifically expressed in XZ5 (Spots A4, B1 and C3) but not in both of XZ54 and ZAU3. These proteins may play crucial roles in drought-tolerance in XZ5. Coding Sequences (CDS) of rbcL and Trx-M genes from XZ5, XZ54 and ZAU3 were cloned and sequenced. CDS length of rbcL and Trx-M was 1401 bp (the partial-length CDS region) and 528 bp (full-length CDS region), respectively, encoding 467 and 176 amino acids. Comparison of gene sequences among XZ5, XZ54 and ZAU3 revealed 5 and 2 SNPs for rbcL and Trx-M, respectively, with two 2 SNPs of missense mutation in the both genes.ConclusionsOur findings highlight the significance of specific-proteins associated with drought tolerance, and verified the potential value of Tibetan wild barley in improving drought tolerance of barley as well as other cereal crops.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1657-3) contains supplementary material, which is available to authorized users.

Background To investigate the biological relationship, mechanism between perilipin2 and the occurrence, advancement of gastric carcinoma, and explore the mechanism of lipid metabolism disorder leading to gastric neoplasm, and propose that perilipin2 is presumably considered as a potential molecular biomarker of gastric carcinoma. Methods RNA-seq was applied to analyze perilipin2 and differentially expressed genes modulated by perilipin2 in neoplastic tissues of both perilipin2 overexpression and knockdown groups in vivo. The mechanism was discovered and confirmed by Rt-qPCR, immunoblotting, immunohistochemistry, staining and microassay, respectively. Cellular function experiments were performed by flow cytometry, CCK8, clonogenic assay, etc. Results Overexpression and knockdown of perilipin2 augmented the proliferation and apoptosis of gastric carcinoma cell lines SGC7901 and MGC803, respectively. The neoplastic cells with perilipin2-overexpression obtained more conspicuously rapid growth than knockdown group in vivo, and perilipin2 affected the proliferation and apoptosis of gastric carcinoma cells by modulating the related genes:acyl-coa synthetase long-chain family member 3, arachidonate 15-lipoxygenase, microtubule associated protein 1 light chain 3 alpha, pr/set domain 11 and importin 7 that were participated in Ferroptosis pathway. Moreover, RNA-seq indicated perilipin2 was an indispensable gene and protein in the suppression of Ferroptosis caused by abnormal lipometabolism in gastric carcinoma. Conclusion Our study expounded the facilitation of perilipin2 in regulating the proliferation and apoptosis of gastric carcinoma cells by modification in Ferroptosis pathway, and we interpreted that the mechanism of gastric neoplasm caused by obesity, we also discovered that pr/set domain 11 and importin 7 are novel transcription factors relevant to gastric carcinoma. Furthermore, perilipin2 probably serves not only as a diagnostic biomarker, but also a new therapeutic target.

Pancreatic cancer remains one of the leading causes of cancer-related deaths worldwide. Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic tumor. Many circular RNAs (circRNAs) have proven to play vital roles in the physiological and pathological processes of tumorigenesis; however, their biogenesis in PDAC remains unclear. In this study, the expression profiles of circRNAs from 10 PDAC tissues and their paired adjacent nontumor tissues were analyzed through RNA sequencing analysis. An enrichment analysis was employed to predict the functions of the differentially expressed circRNAs. Sequence alignment information and mRNA microarray projects were used to predict the RNA regulatory network. The knockdown of circRNAs by small interfering RNAs followed by wound healing and western blot assays was used to confirm their functions in a PDAC cell line. A total of 278 circRNAs were identified as differentially expressed in PDAC tissue. Of these, we found that hsa_circRNA_0007334 was significantly upregulated and may serve as a competing endogenous RNA to regulate matrix metallopeptidase 7 (MMP7) and collagen type I alpha 1 chain (COL1A1) by the competitive adsorption of hsa-miR-144-3p and hsa-miR-577 to enhance the expression and functions of MMP7 and COL1A1 in PDAC. In vitro experiments confirmed these results. The present study is the first to propose two regulatory pathways in PDAC: hsa_circRNA_0007334–hsa-miR-144-3p–MMP7 and hsa_circRNA_0007334–hsa-miR-577–COL1A1.

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BackgroundCadmium (Cd) is a severe detrimental environmental pollutant. To adapt to Cd-induced deleterious effects, plants have evolved sophisticated defence mechanisms. In this study, a genome-wide transcriptome analysis was performed to identify the mechanisms of Cd tolerance using two barley genotypes with distinct Cd tolerance.ResultsMicroarray expression profiling revealed that 91 genes were up-regulated by Cd in Cd-tolerant genotype Weisuobuzhi and simultaneously down-regulated or non-changed in Cd-sensitive Dong17, and 692 genes showed no change in Weisuobuzhi but down-regulated in Dong17. Novel genes that may play significant roles in Cd tolerance were mainly via generating protectants such as catalase against reactive oxygen species, Cd compartmentalization (e.g. phytochelatin-synthase and vacuolar ATPase), and defence response and DNA replication (e.g. chitinase and histones). Other 156 up-regulated genes in both genotypes also included those encoding proteins related to stress and defence responses, and metabolism-related genes involved in detoxification pathways. Meanwhile, biochemical and physiological analysis of enzyme (ATPase and chitinase), phytohormone (ethylene), ion distribution and transport (Cd, Na+, K+, Ca2+, ABC transporter) demonstrated that significantly larger Cd-induced increases of those components in Weisuobuzhi than those in Dong17. In addition, Cd-induced DNA damage was more pronounced in Dong17 than that in Weisuobuzhi.ConclusionsOur findings suggest that combining microarray, physiological and biochemical analysis has provided valuable insights towards a novel integrated molecular mechanism of Cd tolerance in barley. The higher expression genes in Cd tolerant genotype could be used for transgenic overexpression in sensitive genotypes of barley or other cereal crops for elevating tolerance to Cd stress.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-611) contains supplementary material, which is available to authorized users.