Transcription profiling of Pectobacterium atrosepticum wild and ExpI mutants to determine the quorum sensing regulon
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ABSTRACT: Genome-wide in planta determination of the quorum sensing regulon in Pectobacterium atrosepticum, through gene expression analysis of ExpI mutants using Agilent custom microarrays.
Project description:Plant cell wall degrading enzymes (PCWDEs) are key virulence determinants in the pathogenesis of the potato pathogen, Pectobacterium atrosepticum. In this study, we report the impact on virulence of a transposon insertion mutation in the metJ gene that codes for the repressor of the methionine biosynthesis regulon. In a mutant strain defective for the small regulatory RNA rsmB, PCWDEs are not produced and virulence in potato tubers is almost totally abolished. However, when the metJ gene is disrupted in this background, the rsmB- phenotype is suppressed and virulence and PCWDE production are restored. Additionally, when metJ is disrupted, production of the quorum sensing signal, N-(3-oxohexanoyl)-homoserine lactone, is induced precociously. The metJ mutant strains showed pleiotropic transcriptional impacts affecting approximately a quarter of the genome. Genes involved in methionine biosynthesis were most highly up-regulated, but many virulence-associated transcripts were also upregulated. This is the first report of the impact of the MetJ repressor on virulence in bacteria.
Project description:The aim of this study was to conduct a genome-wide analysis for constituent tuber carotenoid QTL. Using a genetical genomics approach samples from clones with similar carotenoid traits were bulked and patterns of gene expression were measured for each bulk by microarray analysis. Variation of gene expression within these bulks may be due to either polymorphisms located near to or within the gene (cis-eQTL) or indirectly from a distant location on the genome (trans-eQTL). Differentially expressed clones from bulks with contrasting carotenoid traits were genetically mapped in order to re-enforce the QTL analysis, and provide a rapid means of developing gene markers closely associated with the target traits.
Project description:Transcript-Level Variation in Barley Seedling Leaves Challenged with Puccinia hordei and the Molecular Basis of Partial Resistance to Leaf Rust
Project description:Transcript-Level Variation in Barley Seedling Leaves Challenged with Puccinia hordei and the Molecular Basis of Partial Resistance to Leaf Rust