Project description:Plant drought stress response and resistance are complex biological processes that merit systems-level analyses to dissect drought stress encountered by crops in the field. We have used gene expression profiling of Arabidopsis plants subjected to a controlled, sublethal, moderate drought (mDr) treatment to characterize early and late response to drought. We have also compared these profiles to those from plants treated with soil water deficit (progressive) drought (pDr) to reveal acclimation responses in plants.
Project description:The leaf transcriptome of the Arabidopsis thaliana aquaporin gene PIP1;2 T-DNA insertion line was compared to that of control plants. In total 730 genes were found to be differentially regulated. This regulation pattern was compared to mild drought stress and low CO2 Affymetrix data to elucidate whether loss of the aquaporin resembles transcriptomic changes of drought stress or lack of CO2 supply. Mild drought stress data were obtained from Harb A, Krishnan A, Ambavaram MMR, Pereira A (2010) Molecular and Physiological Analysis of Drought Stress in Arabidopsis Reveals Early Responses Leading to Acclimation in Plant Growth. Plant Physiology 154: 1254-1271 (GSE24177). Low CO2 data were obtained from Oliver E. Bläsing, Yves Gibon, Manuela Günther, Melanie Höhne, Rosa Morcuende, Daniel Osuna, Oliver Thimm, Björn Usadel, Wolf-Rüdiger Scheible, and Mark Stitt (2005) Sugars and Circadian Regulation Make Major Contributions to the Global Regulation of Diurnal Gene Expression in Arabidopsis. The Plant Cell, Vol. 17, 3257-3281 (GSE3423). 2 samples examined: wildtype and atpip1;2-1 mutant
Project description:The leaf transcriptome of the Arabidopsis thaliana aquaporin gene PIP1;2 T-DNA insertion line was compared to that of control plants. In total 730 genes were found to be differentially regulated. This regulation pattern was compared to mild drought stress and low CO2 Affymetrix data to elucidate whether loss of the aquaporin resembles transcriptomic changes of drought stress or lack of CO2 supply. Mild drought stress data were obtained from Harb A, Krishnan A, Ambavaram MMR, Pereira A (2010) Molecular and Physiological Analysis of Drought Stress in Arabidopsis Reveals Early Responses Leading to Acclimation in Plant Growth. Plant Physiology 154: 1254-1271 (GSE24177). Low CO2 data were obtained from Oliver E. Bläsing, Yves Gibon, Manuela Günther, Melanie Höhne, Rosa Morcuende, Daniel Osuna, Oliver Thimm, Björn Usadel, Wolf-Rüdiger Scheible, and Mark Stitt (2005) Sugars and Circadian Regulation Make Major Contributions to the Global Regulation of Diurnal Gene Expression in Arabidopsis. The Plant Cell, Vol. 17, 3257-3281 (GSE3423).
Project description:Plant drought stress response and resistance are complex biological processes that merit systems-level analyses to dissect drought stress encountered by crops in the field. We have used gene expression profiling of Arabidopsis plants subjected to a controlled, sublethal, moderate drought (mDr) treatment to characterize early and late response to drought. We have also compared these profiles to those from plants treated with soil water deficit (progressive) drought (pDr) to reveal acclimation responses in plants. Controlled moderate drought (mDr) was maintained by giving Arabidopsis (Columbia) plants water to keep the soil moisture level at 30% of field capacity, which is 200% or 2 g H2O g-1 dry soil. Water was withheld at 30 days after sowing (DAS). For progressive drought (pDr) treatment, plants were grown in a growth room as described above, water was withheld at 35 DAS, and were allowed to dry until the required pDr level was reached. For RNA isolation, two biological replicate samples of 5 pooled plants were collected at early (day1) and late stage (day10) for mDr, and first day of wilting for pDr, along with controls for mDr and pDr. Samples were hybridized to the Affymetrix (ATH1 25K) GeneChip.
Project description:Plants acclimate to environmental fluctuations by transitory reconfigurations the homeostatic network. Primary studies suggested that transcriptome responses to deal with fluctuations in light intensity and temperature tend to reversibility after stress removal in the model plant Arabidopsis thaliana. To gain more insight into this pattern in the context of acclimation, RNA-Seq analysis were conducted in Arabidopsis thaliana after different abiotic stress treatments consisting in high light (HL), high humidity, drought, heat, cold and combinations among factors or after recovery periods. Our transcriptome study is in line of a general pattern wherby transcriptome changes in response to adverse environments are prone to return to the basal state during the de-acclimation phase.
Project description:Arabidopsis seedling were exposed in co-culture to E. amylovora mVOC and data show that mVOCs promote plant growth and early responses
Project description:With frequent fluctuations in global climate, plants often experience co-occurring dry-wet cycles and pathogen infection and this combination adversely affects plant survival. In the past, some studies indicated that morpho-physiological responses of plants to the combined stress are different from the individual stressed plants. However, interaction of drought stressed or drought recovered plants with pathogen has not been widely studied at molecular level. Such studies are important to understand the defense pathways that operate as part of combined stress tolerance mechanism. In this study, Arabidopsis plants were exposed to individual drought stress (soil drying at 40% FC, D), Pseudomonas syringae pv tomato DC3000 (PStDC3000), infection and their combination. Plants recovered from drought stress were also exposed to PStDC3000. Beside we have also infiltrated P. syringae pv tabaci (PSta, non-host pathogen) individually or in combination with drought stress. Using Affymetrix WT gene 1.0 ST array, global transcriptome profiling of plants leaves under individual drought stress and pathogen infection was compared with their combination. Results implicate that plants exposed to combined drought and pathogen stress experience a new state of stress where each combination of stressor and their timing defines the plant responses and thus should be studied explicitly. Global transcriptional analysis in Arabidopsis leaves exposed to individual and combined drought and pathogen stress.
Project description:Plants balance their conflicting requirements for growth and stress tolerance via sophisticated pathways and unique genes that control responses to the external environment. We have identified a novel plant-specific gene, COST1(Constitutively Stressed 1), that affects plant growth and negatively regulates drought resistance by manipulating the autophagy pathway. An Arabidopsis cost1 mutant has decreased growth and increased drought tolerance, together with constitutive autophagy and increased expression of drought-response genes. The COST1 protein is degraded upon plant dehydration, and this degradation is blocked by treatment with inhibitors of the 26S proteasome or autophagy pathways. The cost1 mutant drought resistance is dependent on an active autophagy pathway, indicating that COST1 acts through manipulation of autophagy. COST1 co-localizes to autophagosomes with the autophagosome marker ATG8e and the autophagy adaptor NBR1, and physically interacts with ATG8e, indicating a pivotal role in direct regulation of autophagy. We propose a model in which COST1 represses autophagy under optimal conditions, thus allowing plant growth. During drought, COST1 is degraded, enabling activation of autophagy and suppressing growth to enhance drought tolerance.
Project description:Genome-wide transcriptional profiling of Arabidopsis thaliana to a combination of heatwave and drought under ambient and elevated CO2. Goal of this study was elucidate the transcriptional responses to a combination of heat wave and drought, and to see how these responses are modifed under future climate (high) CO2. Climate changes increasingly threaten plant growth and productivity. Such changes are complex and involve multiple environmental factors, including rising CO2 levels and climate extreme events. As the molecular and physiological mechanisms underlying plant responses to realistic future climate extreme conditions are still poorly understood, a multiple organizational level-analysis (i.e. eco-physiological, biochemical and transcriptional) was performed, using Arabidopsis exposed to incremental heat wave and water deficit under elevated CO2.The climate extreme resulted in biomass reduction, photosynthesis inhibition, and considerable increases in stress parameters. Photosynthesis was a major target as demonstrated at the physiological and transcriptional levels. In contrast, the climate extreme treatment induced a protective effect on oxidative membrane damage, most likely as a result of strongly increased lipophilic antioxidants and membrane-protecting enzymes. Elevated CO2 significantly mitigated the negative impact of a combined heat and drought, as apparent in biomass reduction, photosynthesis inhibition, chlorophyll fluorescence decline, H2O2 production and protein oxidation. Analysis of enzymatic and molecular antioxidants revealed that the stress-mitigating CO2 effect operates through up-regulation of antioxidant defense metabolism, as well as by reduced photorespiration resulting in lowered oxidative pressure. Therefore, exposure to future climate extreme episodes will negatively impact plant growth and production, but elevated CO2 is likely to mitigate this effect.
Project description:Drought is a major abiotic stress that threatens global food security. Circular RNAs (circRNAs) are endogenous RNAs. How these molecules influence plant stress responses remains elusive. Here, a large scale circRNA profiling identified 2174 and 1354 high-confidence circRNAs in maize and Arabidopsis, respectively, and most were differentially expressed in response to drought. A substantial number of drought-associated circRNA hosting genes were involved in conserved or species-specific pathways in drought responses. Comparative analysis revealed that circRNA biogenesis was more complex in maize than in Arabidopsis. In most cases, maize circRNAs were negatively correlated with sRNA accumulation. In 368 maize inbred lines, the circRNA-hosting genes were enriched for SNPs associated with circRNA expression and drought tolerance, implying either important roles of circRNAs in maize drought responses or their potential use as biomarkers for breeding drought-tolerant maize. Additionally, the expression levels of circRNAs derived from drought-responsible genes encoding calcium-dependent protein kinase and cytokinin oxidase/dehydrogenase were significantly associated with drought tolerance of maize seedlings. Specifically, Arabidopsis plants overexpressing circGORK (Guard cell outward-rectifying K+-channel) were hypersensitive to ABA, but insensitive to drought, suggesting a positive role of circGORK in drought tolerance. We report the transcriptomic profiling and transgenic studies of circRNAs in plant drought responses, and provide evidences highlighting the universal molecular mechanisms involved in plant drought tolerance.