Project description:Background: Microorganisms are the major cause of food spoilage during storage, processing and distribution. Pseudomonas fluorescens is a typical spoilage bacterium that contributes to a large extent to the spoilage process of proteinaceous food. RpoS is considered an important global regulator involved in stress survival and virulence in many pathogens. Our previous work revealed that RpoS contributed to the spoilage activities of P. fluorescens by regulating resistance to different stress conditions, extracellular acylated homoserine lactone (AHL) levels, extracellular protease and total volatile basic nitrogen (TVB-N) production. However, RpoS-dependent genes in P. fluorescens remained undefined. Results: RNA-seq transcriptomics analysis combined with quantitative proteomics analysis basing on multiplexed isobaric tandem mass tag (TMT) labeling was performed for the P. fluorescens wild-type strain UK4 and its derivative carrying a rpoS mutation. A total of 375 differentially expressed genes (DEGs) and 212 differentially expressed proteins (DEPs) were identified in these two backgrounds. The DGEs were further verified by qRT-PCR tests, and the genes directly regulated by RpoS were confirmed by 5’-RACE-PCR sequencing. The combining transcriptome and proteome analysis revealed a role of this regulator in several cellular processes, including polysaccharide metabolism, intracellular secretion and extracellular structures, cell well biogenesis, stress responses, ammonia and biogenic amine production, which may contribute to biofilm formation, stress resistance and spoilage activities of P. fluorescens. Moreover, in this work we indeed observed that RpoS contributed to the production of the macrocolony biofilm’s matrix.
Project description:An experiment was performed to predict citrus varieties by means of supervised learning algorithms applied to gene expression profiles
Project description:The goal of this experiment is to evaluate the potential for utilising this oligonucleotide microarray in other species and genera of the Pinaceae family by using comparative RNA hybridizations in four different spruces (Picea spp), two pines (Pinus spp.) and a larch (Larix laricina), across two tissues, xylem and phelloderm. One-color comparison of 7 conifer species in 2 tissue types: xylem and phelloderm. Between 4 and 28 biological repetitions per sample type, depending on the species, for a total of 142 slides.
Project description:We report the discovery of a beta-glucosidase gene (PgM-NM-2glu-1) whose expression underpins natural resistance to a major forest pest, the spruce budworm (SBW) in white spruce (Picea glauca (Voss.) Moench). We performed a microarray experiment to compare resistant (R) and non-resistant (N-R) trees. PgM-NM-2glu-1 transcripts levels uniquely were up to 1000 times higher in phenotypically resistant trees and correlated with accumulation of acetophenones compounds that reduce SBW development. These resistance traits were heritable, temporally correlated with the emergence of the most damaging larval stages and were highly variable in the natural population across a large geographic area. The recombinant gene product specifically catalyzed the release of biologically active acetophenones from their glucoside precursors. SBW outbreaks have become more frequent and intense; therefore, the phenotypic diversity resulting from variation in PgM-NM-2glu-1 expression may be a key for the adaptability of spruce populations. Transcriptome profiling was carried out with needles from 7 resistant and 7 non-resistant trees (harvested on June 17th, 2010), and 3 samples per tree (n=42) with a custom microarray developed for spruce species and comprising oligonucleotide probes for 23,853 unique P. glauca gene sequences (Raherison et al., 2012).
Project description:The goal is to identify tissue specific patterns of expression in Picea glauca seedlings One-color comparison of seven tissues of white spruce. Four biological repetitions per tissue (non-related trees), repeated in two channels as technical replicates, for a total of 56 slides.
Project description:Most sRNAs control the expression of target genes by interacting with their mRNA. The fvr1 (Francisella virulence RNA 1) gene is found in the IGR between FTL_0777 and FTL_0778 and its sequence does not overlap those of the flanking genes, indicating that its target(s) is located in trans. Base-pairing between a sRNA and target mRNA generally leads to changed translation and often the stability of the mRNA is affected as well. Therefore, to identify possible targets of Fvr1, we compared the transcriptomes of the LVS?fvr1(LVS, for Live Vaccine Strain) and LVS/pfvr1+ strains after growth in liquid broth.