Transcriptome analysis of bread wheat leaves in response to salt stress.

Salinity is one of the main abiotic stresses limiting crop productivity. In the current study, the transcriptome of wheat leaves in an Iranian salt-tolerant cultivar (Arg) was investigated in response to salinity stress to identify salinity stress-responsive genes and mechanisms. More than 114 million reads were generated from leaf tissues by the Illumina HiSeq 2500 platform. An amount of 81.9% to 85.7% of reads could be mapped to the wheat reference genome for different samples. The data analysis led to the identification of 98819 genes, including 26700 novel transcripts. A total of 4290 differentially expressed genes (DEGs) were recognized, comprising 2346 up-regulated genes and 1944 down-regulated genes. Clustering of the DEGs utilizing Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated that transcripts associated with phenylpropanoid biosynthesis, transporters, transcription factors, hormone signal transduction, glycosyltransferases, exosome, and MAPK signaling might be involved in salt tolerance. The expression patterns of nine DEGs were investigated by quantitative real-time PCR in Arg and Moghan3 as the salt-tolerant and susceptible cultivars, respectively. The obtained results were consistent with changes in transcript abundance found by RNA-sequencing in the tolerant cultivar. The results presented here could be utilized for salt tolerance enhancement in wheat through genetic engineering or molecular breeding.

Salt tolerance involved candidate genes in rice: an integrative meta-analysis approach.

BACKGROUND: Salinity, as one of the main abiotic stresses, critically threatens growth and fertility of main food crops including rice in the world. To get insight into the molecular mechanisms by which tolerant genotypes responds to the salinity stress, we propose an integrative meta-analysis approach to find the key genes involved in salinity tolerance. Herein, a genome-wide meta-analysis, using microarray and RNA-seq data was conducted which resulted in the identification of differentially expressed genes (DEGs) under salinity stress at tolerant rice genotypes. DEGs were then confirmed by meta-QTL analysis and literature review. RESULTS: A total of 3449 DEGs were detected in 46 meta-QTL positions, among which 1286, 86, 1729 and 348 DEGs were observed in root, shoot, seedling, and leaves tissues, respectively. Moreover, functional annotation of DEGs located in the meta-QTLs suggested some involved biological processes (e.g., ion transport, regulation of transcription, cell wall organization and modification as well as response to stress) and molecular function terms (e.g., transporter activity, transcription factor activity and oxidoreductase activity). Remarkably, 23 potential candidate genes were detected in Saltol and hotspot-regions overlying original QTLs for both yield components and ion homeostasis traits; among which, there were many unreported salinity-responsive genes. Some promising candidate genes were detected such as pectinesterase, peroxidase, transcription regulator, high-affinity potassium transporter, cell wall organization, protein serine/threonine phosphatase, and CBS domain cotaining protein. CONCLUSIONS: The obtained results indicated that, the salt tolerant genotypes use qualified mechanisms particularly in sensing and signalling of the salt stress, regulation of transcription, ionic homeostasis, and Reactive Oxygen Species (ROS) scavenging in response to the salt stress.

Ascorbate biosynthesis and its involvement in stress tolerance and plant development in rice (Oryza sativa L.).

Ascorbic acid (AsA) biosynthesis and its implications for stress tolerance and plant development were investigated in a set of rice knock-out (KO) mutants for AsA biosynthetic genes and their wild-types. KO of two isoforms of GDP-D-mannose epimerase (OsGME) reduced the foliar AsA level by 20-30%, and KO of GDP-L-galactose phosphorylase (OsGGP) by 80%, while KO of myo-inositol oxygenase (OsMIOX) did not affect foliar AsA levels. AsA concentration was negatively correlated with lipid peroxidation in foliar tissue under ozone stress and zinc deficiency, but did not affect the sensitivity to iron toxicity. Lack of AsA reduced the photosynthetic efficiency as represented by the maximum carboxylation rate of Rubisco (Vmax), the maximum electron transport rate (Jmax) and the chlorophyll fluorescence parameter ΦPSII. Mutants showed lower biomass production than their wild-types, especially when OsGGP was lacking (around 80% reductions). All plants except for KO mutants of OsGGP showed distinct peaks in foliar AsA concentrations during the growth, which were consistent with up-regulation of OsGGP, suggesting that OsGGP plays a pivotal role in regulating foliar AsA levels during different growth stages. In conclusion, our data demonstrate multiple roles of AsA in stress tolerance and development of rice.

Echocardiographic Evaluation of the Relationship Between inflammatory factors (IL6, TNFα, hs-CRP) and Secondary Pulmonary Hypertension in patients with COPD. A Cross sectional study.

BACKGROUND: Inflammatory mechanism appears to play a major role in the pathogenesis of various types of human pulmonary hypertension such as idiopathic PAH (IPAH) and PAH associated" with connective tissue disease. Although we know that inflammatory factors such as IL6 and TNFα have an important role in IPAH, there is limited information about the relationship between acute phase reactants and pulmonary hypertension occurring secondary to pulmonary diseases such as chronic obstructive pulmonary diseases (COPD). METHODS: This cross-sectional study was carried out on 94 patients who had COPD. Patients with a recent history of systemic steroid and acetylsalicylic acid (ASA) use, infection, trauma or surgery, gastrointestinal bleeding, coronary artery disease (CAD) and Hypertension were excluded. Body plethysmography and transthoracic echocardiography were done. Blood samples for each patient included were drawn for complete blood count (CBC), IL6, TNFα and highly sensitive C reactive protein (hs-CRP). RESULTS: Twenty patients (28.6%) had pulmonary hypertension. The difference between the mean IL6 and hs-CRP in patients with and without pulmonary hypertension was significant (7 pg/ml vs. 4.4 pg/ml and 13.04 pg/ml vs. 3.31 pg/ml) (p=0.006 and p=0.000). There was a correlation between IL6 and mean pulmonary arterial pressure (r=0.35, p=0.003). After adjustment forage, sex, serum Hemoglobin, Hematocrit, O2Sat, FEV1, FVC the relationship between the IL6, hs-CRP and the presence of pulmonary hypertension remained significant (p=0.022, p=0.026). CONCLUSION: Inflammatory factors such as IL6 and hs-CRP are independent risk factors for pulmonary hypertension in COPD patients.