Project description:The identification of processes activated by specific microbes during microbiota colonization of plant roots has been hampered by technical constraints in metatranscriptomics. These include lack of reference genomes, high representation of host or microbial rRNA sequences in datasets, or difficulty to experimentally validate gene functions. Here, we recolonized germ-free Arabidopsis thaliana with a synthetic, yet representative root microbiota comprising 106 genome-sequenced bacterial and fungal isolates. We used multi-kingdom rRNA depletion, deep RNA-sequencing and read mapping against reference microbial genomes to analyse the in-planta metatranscriptome of abundant colonizers. We identified over 3,000 microbial genes that were differentially regulated at the soil-root interface. Translation and energy production processes were consistently activated in planta, and their induction correlated with bacterial strains’ abundance in roots. Finally, we used targeted mutagenesis to show that several genes consistently induced by multiple bacteria are required for root colonization in one of the abundant bacterial strains (a genetically tractable Rhodanobacter). Our results indicate that microbiota members activate strain-specific processes but also common gene sets to colonize plant roots.
2023-11-03 | GSE231841 | GEO
Project description:Spoilage microbiota in retail packaged broiler meat
Project description:A prototype oligonucleotide microarray was designed to detect and identify viable bacterial species with the potential to grow of common beer spoilage microorganisms from the genera Lactobacillus, Megasphaera, Pediococcus and Pectinatus. Probes targeted the intergenic spacer regions (ISR) between 16S and 23S rRNA, which were amplified in a combination of reverse transcriptase (RT) and polymerase chain reaction (PCR) prior to hybridization. This method allows the detection and discrimination of single bacterial species in a complex sample. Furthermore, microarrays using oligonucleotide probes targeting the ISR allow the distinction between viable bacteria with the potential to grow and non-growing bacteria. The results demonstrate the feasibility of oligonucleotide microarrays as a contamination control in food industry for the detection and identification of spoilage microorganisms within mixed population. Keywords: microarray, oligonucleotide, species-specific, detection, beer spoilage bacteria
Project description:Lactococcus piscium strain MKFS47 is a psychrotrophic spoilage lactic acid bacterium, isolated from the cold-stored modified atmosphere packaged broiler filet strips with the first signs of spoilage. For the experiment L. piscium MKFS47 was grown in MRS broth without acetate with 2% glucose, samples were taken at 3h, 5h and 11h in three replicates. The extracted RNA was sequenced using SOLiD 5500XL. RNA-seq reads were mapped against L. piscium MKFS47 genome and were counted per gene using Lifescope software. The experiment was conducted to identify the time-course differential expression of the L. piscium MKFS47 genes.
Project description:Alicyclobacillus acidoterrestris and Alicyclobacillus suci are both guaiacol producers that can cause spoilage in products like juices. To study the genetic underpinnings of guaiacol production, transcriptomics was performed on multiple strains of A. suci and A. acidoterrestris under guaiacol production conditions in apple juice. While guaiacol production was consistently higher by A. acidoterrestris than by A. suci, the gene expression levels associated with guaiacol production (e.g., vdcC, vdcB, vdcD) showed significant variability across strains of both species, suggesting that other factors beyond vdcC transcription influence the amount of guaiacol produced. This research provides insights for beverage producers in assessing spoilage risks and developing more informed mitigation strategies.