Project description:To identify specific gene networks induced in host roots by C. geophilum, we inoculated seedlings of Scots pine simultaneously with C. geophilum and either Suillus granulatus or Rhizopogon roseolus, two common ECM fungi associated to pines. We then measured the differential expression of Scots pine genes in the respective mycorrhizas using oligoarrays.
Project description:To identify specific gene networks induced in host roots by C. geophilum, we inoculated seedlings of Scots pine simultaneously with C. geophilum and either Suillus granulatus or Rhizopogon roseolus, two common ECM fungi associated to pines. We then measured the differential expression of Scots pine genes in the respective mycorrhizas using oligoarrays. We performed 14 hybridizations (NimbleGen) with samples derived from Pinus sylvestris mycorrhiza with Cenococcum geophilum, Rhizopogon roseolus or Suillus granulatus (3 biological replicates each), as well as from non-mycorrhizal control roots (two replicates). Only the Pinus-derived sequences from the array were considered for this analysis. All samples were labeled with Cy3.
Project description:Seasonal wood development results in two distinct wood types: earlywood (EW) and latewood (LW), which is the major cause of wood qaulity variation. We investigate transcriptome reorganization during seasonal wood development in radiata pine using a newly developed 18k cDNA microarrays.
Project description:Seasonal wood development results in two distinct wood types: earlywood (EW) and latewood (LW), which is the major cause of wood qaulity variation. We investigate transcriptome reorganization during seasonal wood development in radiata pine using a newly developed 18k cDNA microarrays. Three sampling trees each at juvenile (5 yrs), transition (9 yrs) and mature (14 yrs) ages (based on the wood rings at breast height) were selected from a plantation forest of radiata pine at Bondo, NSW , Australia (35º 16' 44.04 S, 148º 26' 54.66 E). The sampling trees at juvenile and mature ages were grown within 50 m distance and under similar environment. Two sampling trees at rotation age (30 yrs) were chosen at Yarralumla, ACT, Australia (35° 18' 27'' S, 149° 7' 27.9'' E).
Project description:Boreal toads (Anaxyrus boreas boreas) of the Southern Rocky Mountain population are declining due to the introduction of the chytrid fungus Batrachochytrium dendrobatidis (Bd). Boreal toads in Colorado are generally susceptible to Bd infection, but some Bd-tolerant populations persist in parts of the Southern Rocky Mountain and broader Eastern boreal toad population. We conducted a Bd challenge with lab-reared sibling toads from Bd-susceptible Colorado and purportedly Bd-tolerant Utah populations and report on transcriptomic responses to Bd during late infection in skin and liver tissue. Fewer immune genes were expressed in response to Bd in Colorado toads, but with greater upregulation compared to Utah toads, indicating a dysregulated immune response. Signatures of Bd-tolerance in Utah toads included more moderate upregulation in immune gene expression and a significantly enriched suite of gene functions related to innate and adaptive immune responses. Our transcriptomic results support the notion that Utah toads are tolerant to Bd, rather than resistant, carrying Bd loads similar to Colorado yet having a unique transcriptomic profile and presenting minimal clinical signs of chytridiomycosis. We conclude that closely related populations have divergent transcriptomic responses to Bd with a dysregulated immune response in Bd-susceptible toads.
Project description:In conifer forests of Northern Europe, a pathogenic fungus Heterobasidion annosum attacks the roots of Scots pine and causes mortality. Trees with infection grow slower and produce less timber with reduced quality. Despite applied control methods, such as switching tree species to a non-host species, or stump treatment, root and butt rot continues to be a serious forest health problem. Disease resistance breeding is a less-applied control method which has potential to improve tree health. However, neither conifer genotypes with absolute resistance to Heterobasidion sp. nor robust selection markers for resistance breeding have been found. We studied the responses of various Scots pine genotypes to Heterobasidion annosum infection and mechanic damage in drained peatland. Stems and roots of mature naturally regenerated Scots pine trees growing in drained peatland were either artificially infected with H. annosum or wounded and inoculated with sterile inoculum. Untreated trees from the study sites served as controls. Responses of different Scots pine genotypes to pathogen infection as determined by lesion size were recorded from samples harvested four months after inoculation, and least susceptible and highly susceptible genotypes were selected from the study material. Analysis of terpenoids from both least susceptible and highly susceptible pine genotypes by gas chromatography coupled with mass spectrometry indicates that some monoterpenes and sesquiterpenes are differentially induced depending on the susceptibility level. Transcriptomic microarray analysis was therefore conducted with RNA from stems of the least susceptible and highly susceptible Scots pine genotypes. Gene expression data from cDNA microarray were analysed by comparisons between the treatments, and the genotypes with different resistance level. The aim of the study is to highlight transcripts specific to differing levels of susceptibility.
Project description:The meristem-associated endosymbiont M. extorquens DSM13060 significantly increases needle and root growth of Scots pine (Pinus sylvestris L.) seedlings without producing plant hormones, but by aggregating around host nuclei. Here we studied gene expression of the pine host induced by M. extorquens DSM13060 infection. We selected the time point of 90 days post-inoculation for our analysis based, because at this point, Methylorubrum extorquens DSM13060 has systemically colonized the pine seedlings, being found throughout tissues of roots and shoots.
Project description:Understanding of mechanisms of resistance of forest trees against microbial pathogens is an essential prerequisite for the development of sustainable forestry practices and for the improvement of commercially-grown trees via either conventional breeding or rational genetic engineering. We have studied the transcriptional response of Scots pine trees to Heterobasidion annosum infection under field conditions. By comparing responses of trees to wounding and to fungal inoculation we could identify a set of genes that were specifically responding to fungal infection. We have also investigated a contribution of Scots pine antimicrobial protein Sp-AMP2 to the host antimicrobial defense to evaluate the potential of Sp-AMP genes as molecular markers for resistance breeding.