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- Imran, Qari Muhammad, et al.
(författare)
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WRKYs, the Jack-of-various-Trades, Modulate Dehydration Stress in Populus davidiana-A Transcriptomic Approach
- 2019
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 20:2
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Tidskriftsartikel (refereegranskat)abstract
- Populus davidiana, native to Korea and central Asian countries, is a major contributor to the Korean forest cover. In the current study, using high-throughput RNA-seq mediated transcriptome analysis, we identified about 87 P. davidiana WRKY transcription factors (PopdaWRKY TFs) that showed differential expression to dehydration stress in both sensitive and tolerant cultivars. Our results suggested that, on average, most of the WRKY genes were upregulated in tolerant cultivars but downregulated in sensitive cultivars. Based on protein sequence alignment, P. davidiana WRKYs were classified into three major groups, I, II, III, and further subgroups. Phylogenetic analysis showed that WRKY TFs and their orthologs in Arabidopsis and rice were clustered together in the same subgroups, suggesting similar functions across species. Significant correlation was found among qRT-PCR and RNA-seq analysis. In vivo analysis using model plant Arabidopsis showed that atwrky62 (orthologous to Potri.016G137900) knockout mutants were significantly sensitive to dehydration possibly due to an inability to close their stomata under dehydration conditions. In addition, a concomitant decrease in expression of ABA biosynthetic genes was observed. The AtHK1 that regulates stomatal movement was also downregulated in atwrky62 compared to the wild type. Taken together, our findings suggest a regulatory role of PopdaWRKYs under dehydration stress.
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| 3. |
- Khan, Murtaza, et al.
(författare)
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Nitric oxide-induced AtAO3 differentially regulates plant defense against Pseudomonas syringae pv. tomato in Arabidopsis thaliana
- 2019
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Ingår i: BMC Plant Biology. - : BioMed Central. - 1471-2229.
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Tidskriftsartikel (refereegranskat)abstract
- Background: Exposure of plants to different environmental insults instigates significant changes in the cellular redox tone driven in part by promoting the production of reactive nitrogen species. The key player, nitric oxide (NO) is a small gaseous diatomic molecule, well-known for its signaling role during stress. In this study, we focused on abscisic acid (ABA) metabolism-related genes that showed differential expression in response to the NO donor S-nitroso-L-cysteine (CySNO) by conducting RNA-seq-based transcriptomic analysis.Results: CySNO-induced ABA-related genes were identified and further characterized. Gene ontology terms for biological processes showed most of the genes were associated with protein phosphorylation. Promoter analysis suggested that several cis-regulatory elements were activated under biotic and/or abiotic stress conditions. The ABA biosynthetic gene AtAO3 was selected for validation using functional genomics. The loss of function mutant atao3 was found to differentially regulate oxidative and nitrosative stress. Further investigations for determining the role of AtAO3 in plant defense suggested a negative regulation of plant basal defense and R-gene-mediated resistance. The atao3 plants showed resistance to virulent Pseudomonas syringae pv. tomato strain DC3000 (Pst DC3000) with gradual increase in PR1 gene expression. Similarly, atao3 plants showed increased hypersensitive response (HR) when challenged with Pst DC3000 (avrB). The atgsnor1–3 and atsid2 mutants showed a susceptible phenotype with reduced PR1 transcript accumulation. Drought tolerance assay indicated that atao3 and atnced3 ABA-deficient mutants showed early wilting, followed by plant death. The study of stomatal structure showed that atao3 and atnced3 were unable to close stomata even at 7 days after drought stress. Further, they showed reduced ABA content and increased electrolyte leakage than the wild-type (WT) plants. The quantitative polymerase chain reaction analysis suggested that ABA biosynthesis genes were down-regulated, whereas expression of most of the drought-related genes were up-regulated in atao3 than in WT.Conclusions: AtAO3 negatively regulates pathogen-induced salicylic acid pathway, although it is required for drought tolerance, despite the fact that ABA production is not totally dependent on AtAO3, and that drought-related genes like DREB2 and ABI2 show response to drought irrespective of ABA content.
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| 4. |
- Nabi, Rizwana Begum Syed, et al.
(författare)
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Nitric oxide regulates plant responses to drought, salinity, and heavy metal stress
- 2019
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Ingår i: Environmental and Experimental Botany. - : Elsevier. - 0098-8472 .- 1873-7307. ; 161, s. 120-133
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Tidskriftsartikel (refereegranskat)abstract
- Plants are exposed to diverse abiotic stresses like drought, heat, salinity, and high-metal concentrations at different stages of their life cycle. As protection against stress, plants release signaling molecules that initiate a cascade of stress-adaptation responses leading either to programmed cell death or plant acclimation. Nitric oxide (NO) is a small but important redox signaling molecule that in plants is involved in a diverse range of physiological processes including germination, development, flowering, senescence, and abiotic stress. Although the exact role of NO in plants remains unclear and is species dependent, various studies have suggested a positive correlation between NO accumulations in stress in plants. In this article, we review and discuss the biosynthesis of NO, sources and exogenous application of NO donors under drought, salt, and heavy metal stress. A review of publications indicated that, in general, application of exogenous NO alleviates the negative stress effects in plants and improves antioxidant activity in most plant species. In addition, S-nitrosylation and tyrosine nitration are two NO-mediated posttranslational modification. All these factors are important in protecting plants from diverse stresses and vary with the species. Furthermore, to determine precise mechanisms of action of NO is expected to help in efficient utilization of crop cultivation under stress conditions.
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| 5. |
- Shahid, Muhammad, et al.
(författare)
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Comprehensive Analyses of Nitric Oxide-Induced Plant Stem Cell-Related Genes in Arabidopsis thaliana
- 2019
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Ingår i: Genes. - : MDPI. - 2073-4425. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Plant stem cells are pluripotent cells that have diverse applications in regenerative biology and medicine. However, their roles in plant growth and disease resistance are often overlooked. Using high-throughput RNA-seq data, we identified approximately 20 stem cell-related differentially expressed genes (DEGs) that were responsive to the nitric oxide (NO) donor S-nitrosocysteine (CySNO) after six hours of infiltration. Among these DEGs, the highest number of positive correlations (R ≥ 0.8) was observed for CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) 12. Gene ontology (GO) terms for molecular function showed DEGs associated with signal transduction and receptor activity. A promoter study of these DEGs showed the presence of cis-acting elements that are involved in growth as well as the regulation of abiotic and biotic stress. Phylogenetic analysis of the Arabidopsis stem cell-related genes and their common orthologs in rice, soybean, poplar, and tomato suggested that most soybean stem cell-related genes were grouped with the Arabidopsis CLE type of stem cell genes, while the rice stem cell-related genes were grouped with the Arabidopsis receptor-like proteins. The functional genomic-based characterization of the role of stem cell DEGs showed that under control conditions, the clv1 mutant showed a similar phenotype to that of the wild-type (WT) plants; however, under CySNO-mediated nitrosative stress, clv1 showed increased shoot and root length compared to WT. Furthermore, the inoculation of clv1 with virulent Pst DC3000 showed a resistant phenotype with fewer pathogens growing at early time points. The qRT-PCR validation and correlation with the RNA-seq data showed a Pearson correlation coefficient of >0.8, indicating the significantly high reliability of the RNA-seq analysis.
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