Project description:This study was designed to identify changes in gene expression that occur when corn was grown on different landscape features. Specifically on the backslope or summit/shoulder of a hill. In rolling landscapes, plant available water varies drastically by location and soil type. Almost simultaneously, plants may be flooded out in footslope locations whereas plants in summit locations may be suffering from severe drought. The objective of this study was to determine the influence of landscape position on corn (Zea mays) productivity and gene regulation. Corn was sampled at V12 for plant growth characteristics and transcriptome analysis at summit/shoulder and lower backslope positions. Plants at the summit had 16% less leaf area and biomass compared with plants at the toeslope. Gene expression analysis using microarray chips, transcriptome analysis, and qPCR indicated that plants at the summit had 708 genes down-regulated and 399 genes up-regulated compared to control plants at the lower back slope. GSEA (Gene Set Enrichment Analysis) indicated tolerance to cold, salt, and drying were increased in summit/should plants compared to control toeslope plants. However, nutrient uptake, recovery from wounding, pest and fungal disease resistance, along with photosynthetic capacity were all down-regulated in moderate water stresses plants. These responses suggest that corn preferentially responses to water stress as the expense of its ability to respond to other stresses.
Project description:This study was designed to identify changes in gene expression that occur when corn was grown on different landscape features. Specifically on the backslope or summit/shoulder of a hill. In rolling landscapes, plant available water varies drastically by location and soil type. Almost simultaneously, plants may be flooded out in footslope locations whereas plants in summit locations may be suffering from severe drought. The objective of this study was to determine the influence of landscape position on corn (Zea mays) productivity and gene regulation. Corn was sampled at V12 for plant growth characteristics and transcriptome analysis at summit/shoulder and lower backslope positions. Plants at the summit had 16% less leaf area and biomass compared with plants at the toeslope. Gene expression analysis using microarray chips, transcriptome analysis, and qPCR indicated that plants at the summit had 708 genes down-regulated and 399 genes up-regulated compared to control plants at the lower back slope. GSEA (Gene Set Enrichment Analysis) indicated tolerance to cold, salt, and drying were increased in summit/should plants compared to control toeslope plants. However, nutrient uptake, recovery from wounding, pest and fungal disease resistance, along with photosynthetic capacity were all down-regulated in moderate water stresses plants. These responses suggest that corn preferentially responses to water stress as the expense of its ability to respond to other stresses. Three biological replicates for the control (backslope) and six biological replicate of summit/shoulder-grown plants were collected. The resulting labeled cDNA was hybridized to the 46,000-element maize microarray chip developed by the University of Arizona using their protocol (International Microarray Workshop Handbook, 2009Gardiner et al. 2005). The hybridization scheme was a dual hybridization using a rolling circle balanced dye swap design. Thus we had three to six biological replicates for each growth condition and two technical replicates for each biological sample.
Project description:Tibet is one of the most threatened regions by climate warming, thus understanding how its microbial communities function may be of high importance for predicting microbial responses to climate changes. Here, we report a study to profile soil microbial structural genes, which infers functional roles of microbial communities, aiming to explore potential microbial responses to climate changes via a strategy of space-for-time substitution. Using a microarray-based metagenomics tool named GeoChip 4.0, we showed that microbial communities were distinct for most but not all of the sites. Substantial variations were apparent in stress, N and C cycling genes, but they were in line with the functional roles of these genes. sixty-three samples were collected from four elevations (3200,3400,3600 and 3800 m) along a Tibetan alpine meadow; Three replicates in each treatment
Project description:To effectively monitor microbial populations in acidic environments and bioleaching systems, a comprehensive 50-mer-based oligonucleotide microarray was developed based on most of the known genes associated with the acidophiles. This array contained 1,072 probes in which there were 571 related to 16S rRNA and 501 related to functional genes. Acid mine drainage (AMD) presents numerous problems to the aquatic life and surrounding ecosystems. However, little is known about the geographic distribution, diversity, composition, structure and function of AMD microbial communities. In this study, we analyzed the geographic distribution of AMD microbial communities from twenty sites using restriction fragment length polymorphism (RFLP) analysis of 16S rRNA genes, and the results showed that AMD microbial communities were geographically distributed and had high variations among different sites. Then an AMD-specific microarray was used to further analyze nine AMD microbial communities, and showed that those nine AMD microbial communities had high variations measured by the number of detected genes, overlapping genes between samples, unique genes, and diversity indices. Statistical analyses indicated that the concentrations of Fe, S, Ca, Mg, Zn, Cu and pH had strong impacts on both phylogenetic and functional diversity, composition, and structure of AMD microbial communities. This study provides insights into our understanding of the geographic distribution, diversity, composition, structure and functional potential of AMD microbial communities and key environmental factors shaping them.
Project description:Arctic alpine species experience extended periods of cold and unpredictable conditions during flowering. Thus, often, alpine plants use both sexual and asexual means of reproduction to maximise fitness and ensure reproductive success. We used the arctic alpine perennial Arabis alpina to explore the role of prolonged cold exposure on adventitious rooting. We exposed plants to 4 °C for different durations and scored the presence of adventitious roots on the main stem and axillary branches. Our physiological studies demonstrated the presence of adventitious roots after 21 weeks at 4 °C saturating the effect of cold on this process. Notably, adventitious roots on the main stem developingin specific internodes allowed us to identify the gene regulatory network involved in the formation of adventitious roots in cold using transcriptomics. These data and histological studies indicated that adventitious roots in A. alpina stems initiate during cold exposure and emerge after plants experience growth promoting conditions. While the initiation of adventitious root was not associated with changes of DR5 auxin response and free endogenous auxin level in the stems, the emergence of the adventitious root primordia was. Using the transcriptomic data, we discerned the sequential hormone responses occurring in various stages of adventitious root formation and identified supplementary pathways putatively involved in adventitious root emergence, such as glucosinolate metabolism. Together, our results highlight the role of low temperature during clonal growth in alpine plants and provide insights on the molecular mechanisms involved at distinct stages of adventitious rooting.
Project description:The altitude gradient limits the growth and distribution of alpine plants.Alpine plants have developed strategies to survive the extremely cold conditions prevailing at high altitudes; however, the mechanism underlying the evolution of these strategies remains unknown. The alpine plant Potentilla saundersiana is widespread in the Northwestern Tibetan Plateau. In this study, we conducted a comparative proteomics analysis to investigate the dynamic patterns of protein expression of P. saundersiana located at five different altitudes. We detected and functionally characterized 118 differentially expressed proteins. Our study confirmed that increasing levels of antioxidant proteins, and their respective activities, and accumulation of primary metabolites, such as proline and sugar, confer tolerance to the alpine environment in P. saundersiana. Proteins species associated with the epigenetic regulation of DNA stability and post-translational protein degradation were also involved in this process. Furthermore, our results showed that P. saundersiana modulated the root architecture and leaf phenotype to enhance adaptation to alpine environmental stress through mechanisms that involved hormone synthesis and signal transduction, particularly the cross-talk between auxin and strictosidine. Based on these findings, we conclude that P. saundersiana uses multiple strategies to adapt to the high-altitude environment of the Northwestern Tibetan Plateau.
Project description:Investigation of whole genome gene expression level changes in maize plants (standard maize line B73) in controlled conditions under continuous light. Tissues of the leaf elongation zone were sampled from plants well watered every 12 hours before and after lights on. A nine chip (Biogemma Nimblegen Custom Array) study using total RNA recovered from three replicates (plants) sampled every 12 hours (1h before and 12 and 24h after lights on).
Project description:To effectively monitor microbial populations in acidic environments and bioleaching systems, a comprehensive 50-mer-based oligonucleotide microarray was developed based on most of the known genes associated with the acidophiles. This array contained 1,072 probes in which there were 571 related to 16S rRNA and 501 related to functional genes. Acid mine drainage (AMD) presents numerous problems to the aquatic life and surrounding ecosystems. However, little is known about the geographic distribution, diversity, composition, structure and function of AMD microbial communities. In this study, we analyzed the geographic distribution of AMD microbial communities from twenty sites using restriction fragment length polymorphism (RFLP) analysis of 16S rRNA genes, and the results showed that AMD microbial communities were geographically distributed and had high variations among different sites. Then an AMD-specific microarray was used to further analyze nine AMD microbial communities, and showed that those nine AMD microbial communities had high variations measured by the number of detected genes, overlapping genes between samples, unique genes, and diversity indices. Statistical analyses indicated that the concentrations of Fe, S, Ca, Mg, Zn, Cu and pH had strong impacts on both phylogenetic and functional diversity, composition, and structure of AMD microbial communities. This study provides insights into our understanding of the geographic distribution, diversity, composition, structure and functional potential of AMD microbial communities and key environmental factors shaping them. This study investigated the geographic distribution of Acid Mine Drainages microbial communities using a 16S rRNA gene-based RFLP method and the diversity, composition and structure of AMD microbial communities phylogenetically and functionally using an AMD-specific microarray which contained 1,072 probes ( 571 related to 16S rRNA and 501 related to functional genes). The functional genes in the microarray were involved in carbon metabolism (158), nitrogen metabolism (72), sulfur metabolism (39), iron metabolism (68), DNA replication and repair (97), metal-resistance (27), membrane-relate gene (16), transposon (13) and IST sequence (11).
Project description:We developed a laboratory-scale model to improve our understanding and capacity to assess the biological risks of genetically engineered bacteria and their genetic elements in the natural environment. Our hypothetical scenario concerns an industrial bioreactor failure resulting in the introduction of genetically engineered bacteria to a downstream municipal wastewater treatment plant (MWWTP). As the first step towards developing a model for this scenario, we sampled microbial communities from the aeration basin of a MWWTP at three seasonal time points. Having established a baseline for community composition, we investigated how the community changed when propagated in the laboratory, including cell culture media conditions that could provide selective pressure in future studies. Specifically, using PhyloChip 16S rRNA gene-targeting microarrays, we compared the compositions of sampled communities to those of inoculates propagated in the laboratory in simulated wastewater conditionally amended with various carbon sources (glucose, chloroacetate, D-threonine) or the ionic liquid 1-ethyl-3-methylimidazolium chloride ([C2mim]Cl). Proteobacteria, Bacteroidetes, and Actinobacteria were predominant in aeration basin and laboratory-cultured populations. Laboratory-cultured populations were enriched in Gammaproteobacteria. Enterobacteriaceae and Aeromonadaceae were enriched by glucose, Pseudomonadaceae by chloroacetate and D-threonine, and Burkholderiaceae by high (50 mM) concentrations of chloroacetate. Microbial populations cultured with chloroacetate and D-threonine were more similar to sampled populations than thoes cultured with glucose or [C2mim]Cl. Although observed relative richness in operational taxonomic units was lower for laboratory cultures than for sampled populations, both flask and reactor systems cultured phylogenetically diverse communities. These results importantly provide a foundation for laboratory models of industrial bioreactor failure scenarios.