Project description:Drought is a major limitation to the growth and productivity of trees in the ecologically and economically important genus Populus. The ability of Populus trees to contend with drought is a function of the responsiveness of their genome to this environmental insult, involving reconfiguration of the transcriptome to appropriately remodel growth, development and metabolism. The Populus drought transcriptome is shaped by interspecific genotypic variation, but the extent to which intraspecific variation shapes the drought transcriptome has not yet been examined. Here we test hypotheses aimed at examining the extent of intraspecific variation in the drought transcriptome. Transcriptome remodeling in response to water-deficit conditions was examined in six different Populus balsamifera L. genotypes using Affymetrix GeneChip technology. There were significant differences in the transcriptomes of the genotypes in response to water-deficit conditions; however, a common species-level response could also be identified across all individuals. Genotypes that had more similar drought-responsive transcriptomes also had fewer genotypic differences, as determined by microarray-derived single feature polymorphism (SFP) analysis, suggesting that responses may be conserved across individuals that share a greater degree of genotypic similarity. This work highlights the fact that a core species-level response can be defined; however, the underpinning genotype-derived complexities of the drought response in Populus must be taken into consideration when defining both species- and genus-level responses. 72 arrays total. 6 genotypes, 2 time points. 2 water regimes. 3 biological replicates per treatment
Project description:Drought is a major limitation to the growth and productivity of trees in the ecologically and economically important genus Populus. The ability of Populus trees to contend with drought is a function of the responsiveness of their genome to this environmental insult, involving reconfiguration of the transcriptome to appropriately remodel growth, development and metabolism. The Populus drought transcriptome is shaped by interspecific genotypic variation, but the extent to which intraspecific variation shapes the drought transcriptome has not yet been examined. Here we test hypotheses aimed at examining the extent of intraspecific variation in the drought transcriptome. Transcriptome remodeling in response to water-deficit conditions was examined in six different Populus balsamifera L. genotypes using Affymetrix GeneChip technology. There were significant differences in the transcriptomes of the genotypes in response to water-deficit conditions; however, a common species-level response could also be identified across all individuals. Genotypes that had more similar drought-responsive transcriptomes also had fewer genotypic differences, as determined by microarray-derived single feature polymorphism (SFP) analysis, suggesting that responses may be conserved across individuals that share a greater degree of genotypic similarity. This work highlights the fact that a core species-level response can be defined; however, the underpinning genotype-derived complexities of the drought response in Populus must be taken into consideration when defining both species- and genus-level responses.
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>
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:Illumina high-throughput sequencing was used to analyse the intestinal bacteria of these two species during different wintering periods at Shengjin Lake. We tested whether contact time enhances the trans-species spread of gut bacteria. Our results indicate that although intestinal microflora of hooded crane and the bean goose were different, direct or indirect contact in the mixed-species flock caused the spread of gut bacteria trans-species, and a very high proportion of common pathogens among these two hosts.