Regulation of carbon reserve use in olive trees under heat, drought, and recovery
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ABSTRACT:
ORGANISM(S): Olea europaea
PROVIDER: GSE145100 | GEO | 2020/12/23
REPOSITORIES: GEO
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Project description:Episodic drought stress negatively impacts the health of long-lived trees. Understanding the genetic and molecular mechanisms that underpin response to drought stress is requisite for selecting or enhancing climate change resilience. Here we aim to establish standardized drought stress protocols for transcriptome studies in poplar trees, to determine how hybrid poplars respond to prolonged and uniform exposure to drought; to determine if the responses to moderate and more severe growth-limiting drought stresses were qualitatively or quantitatively different; and, to determine how response to drought changes throughout the day. We established hybrid poplar trees (Populus x ’Okanese’) from unrooted stem cutting with abundant soil moisture for six weeks. We then withheld water to establish three soil water contents reflecting well-watered, moderate, and severe growth-limiting drought conditions. Plants were rewatered as needed for three weeks to maintain the soil water conditions. The mild and severe drought treatments elicited distinct changes in growth and development, photosynthetic rates and global transcriptomic changes. Notably, the time of day of sampling was strongest signal in the transcriptome data and it quantitatively and qualitatively affected drought responsive changes in gene expression. These analyses emphasize the complex nature of drought regulation in long-lived trees.
2021-12-20 | GSE191155 | GEO
Project description:In light of the changes in precipitation and soil water availability expected with climate change, understanding the mechanisms underlying plant responses to water deficit is essential. Toward that end we have conducted an integrative analysis of responses to drought stress in the perennial C4 grass and biofuel crop, Panicum virgatum (switchgrass). Responses to soil drying and re-watering were measured at transcriptional, physiological, and metabolomic levels. To assess the interaction of soil moisture with diel light:dark cycles, we profiled gene expression in drought and control treatments under pre-dawn and mid-day conditions. Soil drying resulted in reduced leaf water potential, gas exchange, and chlorophyll fluorescence along with differential expression of a large fraction of the transcriptome (37%). Many transcripts responded differently depending on time of day (e.g. up-regulation pre-dawn and down-regulation mid-day). Genes associated with C4 photosynthesis were down-regulated during drought, while C4 metabolic intermediates accumulated. Rapid changes in gene expression were observed during recovery from drought, along with increased water use efficiency and chlorophyll fluorescence. Our findings demonstrate that drought responsive gene expression depends strongly on time of day and that gene expression is extensively modified during the first few hours of drought recovery. Analysis of covariation in gene expression, metabolite abundance, and physiology among plants revealed non-linear relationships that suggest critical thresholds in drought stress responses. Future studies may benefit from evaluating these thresholds among diverse accessions of switchgrass and other C4 grasses.
2014-07-01 | GSE57887 | GEO
Project description:In light of the changes in precipitation and soil water availability expected with climate change, understanding the mechanisms underlying plant responses to water deficit is essential. Toward that end we have conducted an integrative analysis of responses to drought stress in the perennial C4 grass and biofuel crop, Panicum virgatum (switchgrass). Responses to soil drying and re-watering were measured at transcriptional, physiological, and metabolomic levels. To assess the interaction of soil moisture with diel light:dark cycles, we profiled gene expression in drought and control treatments under pre-dawn and mid-day conditions. Soil drying resulted in reduced leaf water potential, gas exchange, and chlorophyll fluorescence along with differential expression of a large fraction of the transcriptome (37%). Many transcripts responded differently depending on time of day (e.g. up-regulation pre-dawn and down-regulation mid-day). Genes associated with C4 photosynthesis were down-regulated during drought, while C4 metabolic intermediates accumulated. Rapid changes in gene expression were observed during recovery from drought, along with increased water use efficiency and chlorophyll fluorescence. Our findings demonstrate that drought responsive gene expression depends strongly on time of day and that gene expression is extensively modified during the first few hours of drought recovery. Analysis of covariation in gene expression, metabolite abundance, and physiology among plants revealed non-linear relationships that suggest critical thresholds in drought stress responses. Future studies may benefit from evaluating these thresholds among diverse accessions of switchgrass and other C4 grasses. mRNA profiles of leaf tissue from clonal replicates at various time points during drydown and recovery were generated by deep sequencing 3' mRNA tags using SOLiD.
2014-07-01 | E-GEOD-57887 | biostudies-arrayexpress
Project description:<p>Drought stress negatively impacts microbial activity, but the magnitude of stress responses are likely dependent on a diversity of below ground interactions. Populus trichocarpa individuals and no plant bulk soils were exposed to extended drought (~0.03% gravimetric water content (GWC) after 12d), re-wet, and a 12-d 'recovery' period to determine the effects of plant presence in mediating soil microbiome stability to water stress. Plant metabolomic analyses indicated that drought exposure increased host investment in C and N metabolic pathways (amino acids, fatty-acids, phenolic glycosides) regardless of recovery. Several metabolites positively correlated with root-associated microbial alpha diversity, but not those of soil communities. Soil bacterial community composition shifted with P. trichocarpa presence and with drought relative to irrigated controls, whereas soil fungal composition only shifted with plant presence. However, root fungal communities strongly shifted with drought, whereas root bacterial communities changed to a lesser degree. The proportion of bacterial water-stress opportunistic OTUs (enriched counts in drought) were high (~11%) at the end of drying phases, and maintained after re-wet, and recovery phases in bulk soils, but declined over time in soils with plants present. For root fungi opportunistic OTUs were high at the end of recovery in drought treatments (~17% abundance), although relatively not responsive in soils, particularly planted soils (< 0.5% abundance for sensitive or opportunistic). These data indicate that plants modulate soil and root associated microbial drought responses via tight plant-microbe linkages during extreme drought scenarios, but trajectories after extreme drought vary with plant habitat and microbial functional groups.</p>
2020-06-19 | MTBLS1463 | MetaboLights
Project description:Cotton (Gossypium hirsutum L) is an important crop world wide that provides fiber for the textile industry. Cotton is a perennial plant that stores starch in stems and roots to provide carbohydrates for growth in subsequent seasons. These reserves are not available to produce seed and fiber when cotton is usually grown as an annual crop. Analysis of developing cotton plants indicated that starch levels peaked about the time of first anthesis then began to decline. An earlier peak of levels of starch was occasionally observed and in some greenhouse-grown samples starch increased 2 week after first bloom. Microarray analyses compared gene expression in tissues containing low levels of starch with tissues rapidly accumulating starch. Statistical analysis of differentially expressed genes indicated increased expression among genes associated with carbohydrate metabolism, transcription activity and the proteasome. Genes associated with starch synthesis, starch degradation, sucrose metabolism, hexose metabolism, raffinose synthesis and trehalose synthesis increased in expression in starch accumulating tissues. The anticipated changes in these sugars were largely confirmed by measuring soluble sugars in relevant tissues. We propose that altering expressions of genes and pathways identified in this work could be used to more efficiently mobilize stored carbohydrate to fiber production. Keywords: starch accumulating, stem, root
2009-01-04 | GSE8973 | GEO
Project description:Drought and salt stress severely inhibit plant growth and development. However, the regulatory mechanisms of plants in response to these stresses are not fully understood. Here we find that the expression of a WRKY transcription factor WRKY46 is rapidly induced by drought, salt and oxidative stresses. Mutations of WRKY46 by T-DNA insertion lead to more sensitive to drought and salt stress, whereas, overexpression of WRKY46 exhibits hypersensitive in soil culture with higher water loss rate, but increased tolerance on the agar plates. ABA induced stomatal closing is impaired in the WRKY46 overexpressing line (OV46), which is potentially due to the lower ROS accumulation in the guard cells. Real-time qPCR and GUS activity assay further demonstrate that WRKY46 is expressed in guard cells, but its expression is not affected by dehydration treatment, suggesting different regulatory mechanisms for WRKY46 between guard cells and other WRKY46 expressed tissues. The stomatal movement and conductance assay indicate that WRKY46 is involved in light-dependent stomatal opening. Further microarray analysis reveals that WRKY46 regulates a set of genes involved in cellular osmoprotection and redox homeostasis under dehydration stress. Determinations of ROS and MDA content confirm its role in oxidative detoxification under stress. Furthermore, we find that WRKY46 modulates light-dependent starch metabolism in guard cells via regulating QQS gene expression. Taken together, we demonstrate that WRKY46 plays a role in modulating cellular osmoprotection and redox homeostasis under drought and salt stress, and functions independently in stomatal movement via regulating light-dependent starch metabolism and ROS levels in guard cells. We used microarrays to identify the certain downstream genes regulated by WRKY46 under normal and dehydration conditions.
2015-02-01 | GSE49418 | GEO
Project description:Drought and salt stress severely inhibit plant growth and development. However, the regulatory mechanisms of plants in response to these stresses are not fully understood. Here we find that the expression of a WRKY transcription factor WRKY46 is rapidly induced by drought, salt and oxidative stresses. Mutations of WRKY46 by T-DNA insertion lead to more sensitive to drought and salt stress, whereas, overexpression of WRKY46 exhibits hypersensitive in soil culture with higher water loss rate, but increased tolerance on the agar plates. ABA induced stomatal closing is impaired in the WRKY46 overexpressing line (OV46), which is potentially due to the lower ROS accumulation in the guard cells. Real-time qPCR and GUS activity assay further demonstrate that WRKY46 is expressed in guard cells, but its expression is not affected by dehydration treatment, suggesting different regulatory mechanisms for WRKY46 between guard cells and other WRKY46 expressed tissues. The stomatal movement and conductance assay indicate that WRKY46 is involved in light-dependent stomatal opening. Further microarray analysis reveals that WRKY46 regulates a set of genes involved in cellular osmoprotection and redox homeostasis under dehydration stress. Determinations of ROS and MDA content confirm its role in oxidative detoxification under stress. Furthermore, we find that WRKY46 modulates light-dependent starch metabolism in guard cells via regulating QQS gene expression. Taken together, we demonstrate that WRKY46 plays a role in modulating cellular osmoprotection and redox homeostasis under drought and salt stress, and functions independently in stomatal movement via regulating light-dependent starch metabolism and ROS levels in guard cells. We used microarrays to identify the certain downstream genes regulated by WRKY46 under normal and dehydration conditions. One-week-old Arabidopsis seedlings of wild-type Col-0 (WT) and WRKY46 overexpressing line (46T) with or without dehydration treatment for 1 h were harvested and used for RNA extraction and hybridization to Affymetrix Arabidopsis ATH1 microarrays. The experiment includes 3 biological replicates.
2015-02-01 | E-GEOD-49418 | biostudies-arrayexpress
Project description:Cotton (Gossypium hirsutum L) is an important crop world wide that provides fiber for the textile industry. Cotton is a perennial plant that stores starch in stems and roots to provide carbohydrates for growth in subsequent seasons. These reserves are not available to produce seed and fiber when cotton is usually grown as an annual crop. Analysis of developing cotton plants indicated that starch levels peaked about the time of first anthesis then began to decline. An earlier peak of levels of starch was occasionally observed and in some greenhouse-grown samples starch increased 2 week after first bloom. Microarray analyses compared gene expression in tissues containing low levels of starch with tissues rapidly accumulating starch. Statistical analysis of differentially expressed genes indicated increased expression among genes associated with carbohydrate metabolism, transcription activity and the proteasome. Genes associated with starch synthesis, starch degradation, sucrose metabolism, hexose metabolism, raffinose synthesis and trehalose synthesis increased in expression in starch accumulating tissues. The anticipated changes in these sugars were largely confirmed by measuring soluble sugars in relevant tissues. We propose that altering expressions of genes and pathways identified in this work could be used to more efficiently mobilize stored carbohydrate to fiber production. Keywords: starch accumulating, stem, root Genes expression was compared between cotton stems that were low in starch and accumulating starch. Gene expression was also compared between cotton roots that were low in starch and accumulating starch. A total of three microarrays were used. One dye swap was used. Material from the field were harvested 2 weeks apart. Greenhouse grown material were planted at two week intervals and harvested at the same time. NOTE that the channel representing the low starch material only gave about half of the total signal than the high starch samples. QPCR of 9 genes confirmed differential expression of 8 of them. QPCR also confirmed similar expression of two genes not predicted to be differentially expressed by the microarray analysis. Therefore no correction was made for the apparent difference in the hybridization of high and low starch samples.
2010-06-24 | E-GEOD-8973 | biostudies-arrayexpress
Project description:Drought is one of the most important environmental fluctuations affecting tree growth and survival. Therefore, understanding of physiological and transcriptomic responses of trees to this stress factor will make important contributions to forest health and productivity. Here, we report comparative physiological and microarray based transcriptome analysis between drought resistant (N.62.191) and drought-sensitive (N.03.368.A) black poplar genotypes under well-watered (WWP), moderate drought (MD), severe drought (SD) and post drought re-watering (PDR) conditions. In the study, sensitive genotype exhibited a drought escape strategy with lower leaf water potential, higher reactive oxygen production, complete leaf abscission and subsequent terminal shoot necrosis under drought stress. On the other hand, resistant genotype had a dehydration tolerance indicating highly delayed leaf abscission under drought and fast growing capacity during re-watering conditions. Gene ontology enrichment analysis attributed drought susceptibility of black poplar to significant up-regulation of genes functional in transcription regulation (AP2/ERF, NAC and WRKY), cell wall modification (Expansins), fatty acid metabolism (enoyl-ACP reductase, lipid transport protein particle), protein degradation (endopeptidases), ethylene synthesis (1-aminocyclopropane-1-carboxylate) and riboflavin synthesis (GTP cyclohydrolase II) under drought stress. Transcriptomic comparison indicated significant down-regulation of photosynthesis, electron transport and carbohydrate metabolism related genes under drought stress in sensitive genotype. Although, similar reduction in carbohydrate metabolism was also recorded for resistant genotype, genes related with photosynthesis and electron transport systems were not down regulated even under SD for this genotype. Resistant genotype specific up-regulation of small heat shock proteins (sHSP) and bark storage proteins revealed importance of protein protection and nitrogen remobilization under drought stress, respectively. This is the first study associating BSP production to delayed leaf abscission and drought tolerance in trees.
2015-06-15 | GSE69875 | GEO
Project description:Drought is one of the most important environmental fluctuations affecting tree growth and survival. Therefore, understanding of physiological and transcriptomic responses of trees to this stress factor will make important contributions to forest health and productivity. Here, we report comparative physiological and microarray based transcriptome analysis between drought resistant (N.62.191) and drought-sensitive (N.03.368.A) black poplar genotypes under well-watered (WWP), moderate drought (MD), severe drought (SD) and post drought re-watering (PDR) conditions. In the study, sensitive genotype exhibited a drought escape strategy with lower leaf water potential, higher reactive oxygen production, complete leaf abscission and subsequent terminal shoot necrosis under drought stress. On the other hand, resistant genotype had a dehydration tolerance indicating highly delayed leaf abscission under drought and fast growing capacity during re-watering conditions. Gene ontology enrichment analysis attributed drought susceptibility of black poplar to significant up-regulation of genes functional in transcription regulation (AP2/ERF, NAC and WRKY), cell wall modification (Expansins), fatty acid metabolism (enoyl-ACP reductase, lipid transport protein particle), protein degradation (endopeptidases), ethylene synthesis (1-aminocyclopropane-1-carboxylate) and riboflavin synthesis (GTP cyclohydrolase II) under drought stress. Transcriptomic comparison indicated significant down-regulation of photosynthesis, electron transport and carbohydrate metabolism related genes under drought stress in sensitive genotype. Although, similar reduction in carbohydrate metabolism was also recorded for resistant genotype, genes related with photosynthesis and electron transport systems were not down regulated even under SD for this genotype. Resistant genotype specific up-regulation of small heat shock proteins (sHSP) and bark storage proteins revealed importance of protein protection and nitrogen remobilization under drought stress, respectively. This is the first study associating BSP production to delayed leaf abscission and drought tolerance in trees.
2017-02-28 | GSE76322 | GEO