Project description:Purpose: This study is designed to identify genes and processes that are differentially regulated in corn when it is grown with or without weeds through the entire critical weed free period (to V8) or when weeds were removed early in the critical weed free period (at V4) and the plants were allowed to recover until V8. Methods: Corn was grown as described above in field plots near Brookings SD in 2007 and 2008 and RNA was extracted from the top-most leaf tips from four plants per treatment plot. Unidirectional cDNA illumina sequencing libraries were constructed for each sample (pooled leaf tips from the given plot), and were sequenced (some samples were paired end sequenced and some were single end sequenced - all 100 bases for PE and SE reads), quality trimmed, and analyzed using the Tuxedo suite of programs for SE reads of the forward read libraries for each sample. Results: We identified a small number of genes that were differentially expressed in both years. More importantly, gene set enrichment analysis of the data determined that weeds, when present through the critical weed free period impacted phytochrome signaling, defense responses, photosynthetic processes, oxidative stress responses, and various hormone signaling processes. When weeds were removed at V4 and the plants allowed to recover until V8, the weeds still imprinted impacts on phytochrome signaling, oxidative stress, and defense responses. Thus, it appears that weeds presence through the early portion of the critical weed free period, even after removal, induced processes that reduce corn growth and yield that lasted at least through V8. Conclusions: This study represents the first investigation of the impact of the lasting effects of weeds during the early critical weed free period on the transcriptome of corn, and provides additional data on the impact of weeds through the critical weed free period that augments and confirms much of what was observed in similar microarray studies. Overall design: Experimental Design: Samples all collected at the same developmental stage (V8) from three treatments (control, weedy, and weeds removed followed by recovery), in each of two years (2007 and 2008), with two to three biological replicates of each treatment in each year.
Project description:The capacity of Acinetobacter baumannii to persist and cause infections depends on its interaction with abiotic and biotic surfaces, including those found on medical devices and host mucosal surfaces. However, the extracellular stimuli affecting these interactions are poorly understood. Based on our previous observations, we hypothesized that mucin, a glycoprotein secreted by lung epithelial cells, particularly during respiratory infections, significantly alters A. baumannii’s physiology and its interaction with the surrounding environment. Biofilm, virulence and growth assays showed that mucin enhances the interaction of A. baumannii ATCC 19606T with abiotic and biotic surfaces and its cytolytic activity against epithelial cells while serving as a nutrient source. The global effect of mucin on the physiology and virulence of this pathogen is supported by RNA-Seq data showing that its presence results in the differential transcription of 427 predicted protein-coding genes. The reduced expression of ion acquisition genes and the increased transcription of genes coding for energy production together with the detection of mucin degradation indicate that this host glycoprotein is a nutrient source. The increased expression of genes coding for adherence and biofilm biogenesis on abiotic and biotic surfaces, the degradation of phenylacetic acid and the production of an active type 6 secretion system further supports the role mucin plays in virulence. Taken together, our observations indicate that A. baumannii recognizes mucin as an environmental signal, which triggers a response cascade that allows this pathogen to acquire critical nutrients and promotes host-pathogen interactions that play a critical role in the pathogenesis of bacterial infections. Overall design: RNAseq of Acinetobacter baumannii ATTC19606T, grown in the presence or absence of mucin, was performed for triplicate samples on an Illumina MiSeq platform.
Project description:Anthocyanin induction in plant is considered a general defense response against biotic and abiotic stresses. The infection by Ustilago maydis, the corn smut pathogen, is accompanied with anthocyanin induction in leaf tissue. We revealed that anthocyanin is intentionally induced by the virulence promoting secreted effector protein Tin2. Tin2 protein functions inside plant cells where it interacts with cytoplasmic maize protein kinase ZmTTK1. Tin2 masks an ubiquitin-proteasome degradation motif in ZmTTK1 leading to a more stable active kinase. Active ZmTTK1 controls transcriptional activation of genes in the anthocyanin biosynthesis pathway rerouting phenylalanine away from lignin biosynthesis. Therefore, we performed microarray analysis to understand how maize gene transcription in phenylpropanoid pathway is differentially changed after infection with Ustilago maydis SG200 (wild type) and SG200Dtin2 (anthocyanin-inducing effector mutant). We prepared three biological replicates for mock-inoculated maize (control), SG200-infected maize and SG200Δtin2-infected maize. For 1 sample, we harvested the leaves (1-3cm below injection hole) from 20 plants and pooled them. At 4 days post inoculation, total RNA was extracted.
Project description:To identify factors involved in OPC senescence, we compared gene expressions between OPC-CG4, OPC-FCS and OPC-Rev. We established OPC senescence model system, in which OPC become senescent in the presence of high concentration of FCS. This phenotypes were kept even when the medium was switched to their optimal serum-free medium.
Project description:Through domestication, humans have substantially altered the morphology of Zea mays ssp. parviglumis (teosinte) into the currently recognizable maize. A wealth of archeological and population genetic data has established maize as a model system for studying domestication , genome evolution and the genetics and evolution of complex traits. We used expression profiling of 18,242 genes for 38 diverse maize genotypes and 18 teosinte genotypes to examine how domestication has re-shaped the transcriptome of maize seedlings. We detected evidence for more than 600 genes having significantly different expression levels in maize compared to teosinte as well as 800 genes with significantly altered co-expression profiles reflective of substantial rewiring of the transcriptome since domestication. These genes likely include loci with altered expression due to domestication. The genes with altered expression show a significant enrichment for genes located in regions that previous population genetic analyses have identified as having undergone a selective sweep during maize domestication; thirty-two genes previously identified as putative targets of selection also exhibit altered expression levels and co-expression relationships. We also identified 45 genes with altered, primarily higher, expression in inbred relative to out-crossed teosinte. These genes are over-represented for genes that function in response to biotic stress and may reflect responses to the effects of inbreeding. This study not only documents alterations in the maize transcriptome following domestication and identifies several genes that may have contributed to the evolution of maize but also highlights the complementary information that can be gained by combining gene expression with population genetic analyses. Overall design: A 135,000 feature array was used to profile gene expression levels in above-ground seedling tissue of 38 maize genotypes and 24 teosinte genotypes.
Project description:To identify factors involved in OPC senescence, we compared gene expressions between OPC-CG4, OPC-FCS and OPC-Rev. Overall design: We established OPC senescence model system, in which OPC become senescent in the presence of high concentration of FCS. This phenotypes were kept even when the medium was switched to their optimal serum-free medium.