ABSTRACT: Genome Profiling of Two Black Poplar (Populus nigra L.) Genotypes Differentially Adapted To Drought Stress Indicated Adaptation-Specific Transcripts
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.
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.
Project description:As exposure to episodic drought can impinge significantly on forest health and the establishment of productive tree plantations, there is great interest in understanding the mechanisms of drought response in trees. The ecologically dominant and economically important genus Populus, with its sequenced genome, provides an ideal opportunity to examine transcriptome level changes in trees in response to a drought stimulus. The transcriptome level drought response of two commercially important hybrid Populus clones (P. deltoides · P. nigra, DN34, and P. nigra · P. maximowiczii, NM6) was characterized over a diurnal period using a 4 · 2 · 2 completely randomized factorial ANOVA experimental design (four time points, two genotypes, and two treatment conditions) using Affymetrix Poplar GeneChip microarrays. Notably, the specific genes that exhibited changes in transcript abundance in response to drought differed between the genotypes and/or the time of day that they exhibited their greatest differences. This study emphasizes the fact that it is not possible to draw simple, generalized conclusions about the drought response of the genus Populus on the basis of one species, nor on the basis of results collected at a single time point. The data derived from our studies provide insights into the variety of genetic mechanisms underpinning the Populus drought response, and provide candidates for future experiments aimed at understanding this response across this economically and ecologically important genus.
Project description:<p>Black poplar is a woody species rich in bioactive phenolic compounds with promising pharmaceutical and cosmetic applications. In wild populations, genetic diversity and environmental variability affect phenolic content and bioactivities. Plant tissue culture, conducted under controlled conditions, offers a suitable alternative for industrial bioproduction. The aim of this study was the development of in vitro shoot cultures of black poplar in MagentaTM and RITA® systems for efficient and constant phenolic productivity. Following the initiation of in vitro lines, significant growth enhancement was achieved through line selection. UPLC-QTOF-MS-based untargeted metabolomic analyses were carried out, and allowed the identification of flavan-3-ols, proanthocyanidins, flavonols and salicinoids. As a result, 32 compounds were described for the first time in P. nigra, including 15 metabolites previously identified in other Populus species and 17 additional compounds not yet identified in the Populus genus. The productivity of the major phenolic compounds was substantially higher in the RITA® system, showing a 2.6-fold increase compared to MagentaTM. Targeted metabolomics followed by Principal Component Analysis were performed to study the metabolic changes during 8 weeks of culture in RITA® system. Optimal shoot growth and phenolic content were achieved in RITA® system after 3 weeks of culture. Finally, the effects of both SA and MeJa treatments were characterized by Orthogonal Partial Least Squares Discriminant Analysis and identified flavan-3-ols and proanthocyanidins as biomarkers of both elicitation. In conclusion, in vitro shoot culture in RITA® system and metabolomics studies allowed to design a specific process for efficient bioproduction of black poplar bioactive phenolics.</p>
Project description:As exposure to episodic drought can impinge significantly on forest health and the establishment of productive tree plantations, there is great interest in understanding the mechanisms of drought response in trees. The ecologically dominant and economically important genus Populus, with its sequenced genome, provides an ideal opportunity to examine transcriptome level changes in trees in response to a drought stimulus. The transcriptome level drought response of two commercially important hybrid Populus clones (P. deltoides · P. nigra, DN34, and P. nigra · P. maximowiczii, NM6) was characterized over a diurnal period using a 4 · 2 · 2 completely randomized factorial ANOVA experimental design (four time points, two genotypes, and two treatment conditions) using Affymetrix Poplar GeneChip microarrays. Notably, the specific genes that exhibited changes in transcript abundance in response to drought differed between the genotypes and/or the time of day that they exhibited their greatest differences. This study emphasizes the fact that it is not possible to draw simple, generalized conclusions about the drought response of the genus Populus on the basis of one species, nor on the basis of results collected at a single time point. The data derived from our studies provide insights into the variety of genetic mechanisms underpinning the Populus drought response, and provide candidates for future experiments aimed at understanding this response across this economically and ecologically important genus. 48 arrays total. 2 genotypes (DN34, NM6), 4 time points (midnight, pre-dawn, mid-day, late day), 2 water regimes (well-watered, water-limited). 3 biological replicates per treatment.