Project description:The host range of parasites is an important factor in assessing the dynamics of disease epidemics. The evolution of pathogens to accommodate new hosts may lead to host range expansion, a process the molecular bases of which are largely enigmatic. The fungus Sclerotinia sclerotiorum parasitizes more than 400 plant species from diverse eudicot families while its close relative, S. trifoliorum, is restricted to plants from the Fabaceae family. We analyzed S. sclerotiorum global transcriptome reprogramming on hosts from six botanical families and reveal a flexible, host-specific transcriptional program driven by core and host-response co-expression (SPREx) gene clusters. We generated a chromosome-level genome assembly for S. trifoliorum and found near-complete gene space conservation in broad and narrow host range Sclerotinia species. However, S. trifoliorum showed increased sensitivity to the Brassicaceae defense compound camalexin. Inter-specific transcriptome analyses revealed a lack of transcriptional response to camalexin in S. trifoliorum and provide evidence that cis-regulatory variation associates with the genetic accommodation of Brassicaceae in the Sclerotinia host range. Our work demonstrates adaptive plasticity of a broad host range pathogen with specific responses to different host plants and demonstrates the co-existence of signatures for generalist and polyspecialist life styles in the genome of a plant pathogen. We reason that this mechanism enables the emergence of new disease with no or limited gene flow between strains and species, and could underlie the emergence of new epidemics originating from wild plants in agricultural settings.
Project description:Sclerotinia sclerotiorum is a broad-host range necrotrophic pathogen which is the causative agent of Sclerotinia stem rot (SSR), and a major disease of soybean (Glycine max). A time course transcriptomic analysis was performed in both compatible and incompatible soybean lines to identify pathogenicity and developmental factors utilized by S. sclerotiorum to achieve pathogenic success.
2019-03-18 | GSE121983 | GEO
Project description:Emergence and host range expansion of an epidemic lineage of Ralstonia solanacearum
Project description:Sclerotinia sclerotiorum, a necrotrophic fungal pathogen with a broad host range, causes a devastating disease on soybean called Sclerotinia stem rot (SSR), can lead to losses as high as 50-60%. Resistance mechanisms against SSR are poorly understood. We used high throughput RNAseq approach to decipher the molecular mechanisms governing resistance to S. sclerotiorum in soybean. Transcripts of recombinant inbred lines (RILs) of soybean; susceptible (S) and resistant (R) were analyzed in a time course experiment. This study might provide an important step towards understanding resistance responses of soybean to S. sclerotiorum and identified novel mechanisms and targets.