Project description:The western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte) is an important pest of corn (Zea mays) in the US. Annual crop rotation between corn and soybean (Glycine max) disrupts the corn-dependent WCR lifecycle and was widely adopted to manage WCR. However, this strategy selected for a rotation-resistant (RR) variant with reduced ovipositional fidelity to cornfields. Previous studies indicated that RR-WCR adults exhibit greater tolerance of soybean tissue diet, different gut physiology, and host-microbe interactions compared to wild-types (WT). To identify genetic mechanisms underlying these phenotypic changes, a de novo assembly of the WCR adult gut transcriptome was constructed and used for RNA-sequencing analyses on RNA libraries from different WCR phenotypes (RR and WT) fed with corn or soybean diets. Differential gene expression analyses and network-based methods were used to identify gene modules transcriptionally correlated with the RR phenotype. Gene ontology enrichment analyses on these modules were then conducted to understand their potential functions and biological importance.
Project description:The western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte) is an important pest of corn (Zea mays) in the US. Annual crop rotation between corn and soybean (Glycine max) disrupts the corn-dependent WCR lifecycle and was widely adopted to manage WCR. However, this strategy selected for a rotation-resistant (RR) variant with reduced ovipositional fidelity to cornfields. Previous studies indicated that RR-WCR adults exhibit greater tolerance of soybean tissue diet, different gut physiology, and host-microbe interactions compared to wild-types (WT). To identify genetic mechanisms underlying these phenotypic changes, a de novo assembly of the WCR adult gut transcriptome was constructed and used for RNA-sequencing analyses on RNA libraries from different WCR phenotypes (RR and WT) fed with corn or soybean diets. Differential gene expression analyses and network-based methods were used to identify gene modules transcriptionally correlated with the RR phenotype. Gene ontology enrichment analyses on these modules were then conducted to understand their potential functions and biological importance. Differential gene expression analyses on RNA libraries from adult guts of different WCR phenotypes (rotation-resistant and wild-type) fed with corn or soybean diets
Project description:Bacterial wilt caused by Ralstonia solanacearum is a lethal, soil-borne disease of tomato. Control of the disease with chemicals and crop rotation is insufficient, because the pathogen is particularly well adapted for surviving in the soil and rhizosphere. Therefore, cultivar resistance is the most effective means for controlling bacterial wilt, but the molecular mechanisms of resistance responses remain unclear. We used microarrays to obtain the characteristics of the gene expression changes that are induced by R. solanacearum infection in resistant cultivar LS-89 and susceptible cultivar Ponderosa.
Project description:The melting of permafrost and its potential impact on greenhouse gas emissions is a major concern in the context of global warming. The fate of the carbon trapped in permafrost will largely depend on soil physico-chemical characteristics, among which are the quality and quantity of organic matter, pH and water content, and on microbial community composition. In this study, we used microarrays and real-time PCR (qPCR) targeting 16S rRNA genes to characterize the bacterial communities in three different soil types representative of various Arctic settings. The microbiological data were linked to soil physico-chemical characteristics and CO2 production rates. Microarray results indicated that soil characteristics, and especially the soil pH, were important parameters in structuring the bacterial communities at the genera/species levels. Shifts in community structure were also visible at the phyla/class levels, with the soil CO2 production rate being positively correlated to the relative abundance of the Alphaproteobacteria, Bacteroidetes, and Betaproteobacteria. These results indicate that CO2 production in Arctic soils does not only depend on the environmental conditions, but also on the presence of specific groups of bacteria that have the capacity to actively degrade soil carbon.
Project description:Here we have compared adult wildtype (N2) C. elegans gene expression when grown on different bacterial environments/fod sources in an effort to model naturally occuring nematode-bacteria interactions at the Konza Prairie. We hypothesize that human-induced changes to natural environments, such as the addition of nitrogen fertalizer, have effects on the bacterial community in soils and this drives downstream changes in the structure on soil bacterial-feeding nematode community structure. Here we have used transcriptional profiling to identify candidate genes involved in the interaction of nematodes and bacteria in nature.
Project description:Soil transplant serves as a proxy to simulate climate change in realistic climate regimes. Here, we assessed the effects of climate warming and cooling on soil microbial communities, which are key drivers in Earth’s biogeochemical cycles, four years after soil transplant over large transects from northern (N site) to central (NC site) and southern China (NS site) and vice versa. Four years after soil transplant, soil nitrogen components, microbial biomass, community phylogenetic and functional structures were altered. Microbial functional diversity, measured by a metagenomic tool named GeoChip, and phylogenetic diversity are increased with temperature, while microbial biomass were similar or decreased. Nevertheless, the effects of climate change was overridden by maize cropping, underscoring the need to disentangle them in research. Mantel tests and canonical correspondence analysis (CCA) demonstrated that vegetation, climatic factors (e.g., temperature and precipitation), soil nitrogen components and CO2 efflux were significantly correlated to the microbial community composition. Further investigation unveiled strong correlations between carbon cycling genes and CO2 efflux in bare soil but not cropped soil, and between nitrogen cycling genes and nitrification, which provides mechanistic understanding of these microbe-mediated processes and empowers an interesting possibility of incorporating bacterial gene abundance in greenhouse gas emission modeling.