Project description:This research uses terminal branches from a wild poplar tree to track somatic genetic, epigenetic, and transcriptional changes. Using a multi-omics approach, we aim to identify and describe mutations which arise during the lifetime of a long-lived perennial plant.
Project description:Gene expression profiling in leaves of a free-growing aspen tree (Populus tremula) in Umea in northern Sweden during natural autumn senescence (from August 17 to September 21).
Project description:Populus deltoides and Populus trichocarpa were exposed to either ambient air or an acute ozone exposure of 200 ppb for 9 hrs and ozone response was profiled for each genotype by hybridising control against ozone-exposed samples per genotype. Keywords: stress response, genotype comparrison, ozone exposure RNA was extracted from the fifth leaf below the first fully unfurled leaf for each plant. Control and ozone-exposed plants were then randomly paired for hybridisation.
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.
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. For Microarray experiment total RNA was isolated from the leaves randomly selected from two balck poplar seedlings (two biological replicates) for resistant and sensitive genotypes at well watered period (WWP), moderate drought (MD), severe drought (SD) and post drought rewatering (PDR) periods. For each water availability regime total isolated RNA was loaded onto two Affymetrix poplar Gene Chips for each genotype. Totally 16 Affymetrix poplar GeneChips (2 genotypes × 4 water availability regimes × 2 biological replicates) were used for transcriptional analysis.