Project description:Increasing evidence of Pseudomonas aeruginosa on fresh plant-based foods raises food safety concerns. While internalization of pathogens such as Salmonella enterica in vegetables such as lettuce is well documented, corresponding data for P. aeruginosa are lacking. Moreover, climate change-associated temperature shifts may influence the plant microbiota and the presence of human pathogens. This study investigates the internalization and temperature-dependent gene expression of P. aeruginosa PAO1 on green oak leaf lettuce as a model system. For this purpose, oak leaf lettuce was cultivated in soil inoculated with P. aeruginosa PAO1_sfGFP_UHH07, and internalization was analyzed using confocal laser scanning microscopy. Temperature-dependent transcriptomic changes of P. aeruginosa PAO1 were assessed by analyzing differentially expressed genes following plant inoculation and incubation at 18 and 22 °C, respectively. P. aeruginosa PAO1 is capable of internalizing into the roots of oak leaf lettuce, but a translocation into leaves was not detected. Transcriptomic analyses showed that a moderate temperature increase shifts bacterial gene expression, with virulence genes upregulated at 22 °C and persistence-associated genes predominating at 18 °C. These results show that temperature influences the persistence and pathogenic potential of P. aeruginosa present on oak leaf lettuce, highlighting potential impacts of climate change on food safety.
Project description:The purpose of this study was to make a single comparison between Cqf genes expressed during the vegetative stages of infection on the telial host (oak leaf) versus the aecial host (pine stem). A large proportion of genes were expressed in both hosts and significantly differentially expressed genes were enriched for candidate fungal effectors (small secreted proteins). These results suggest that the Cqf rust fungus uses a largely common set of genes to create two very different infection phenotypes. This study was based on hybridizations to custom microarrays containing features representing 8692 gene models from a Cqf genome sequencing project midpoint assembly. Two Agilent 4 X 44K microarray slides were populated with 60-mer probes (1 to 5 per transcript), designed using AgilentM-bM-^@M-^Ys web-based eArray software. Labeled target cRNA (complementary RNA) was generated using AgilentM-bM-^@M-^Ys Low Input Quick Amp Labeling Kit, such that oak and pine samples were labeled with either cy3 or cy5 an equal number of times across the experiment. Each microarray was hybridized with labeled cRNA target derived from a single oak sample and labeled cRNA target derived from a single pine sample. There were a total of eight oak sample replications and eight pine sample replications. Target hybridization and scanning were performed by the University of FloridaM-bM-^@M-^Ys Interdisciplinary Center for Biotechnology Research using standard procedures and an Agilent G250B Scanner.
Project description:Integrated transcriptomics and metabolomics decipher differences in the resistance of pedunculate oak to the herbivore Tortrix viridana L.
