Project description:Estimating the fitness effect of deleterious mutations during the two phases of the life cycle: a new method applied to the root-rot fungus Heterobasidion parviporum
Project description:Transcript profiles of Heterobasion irregulare from different tissues and mycelium grown on different substrates were analyzed. The array probes were designed from gene models taken from the Joint Genome Institute (JGI, department of energy) Heterobasidion annosum genome sequence version 1. One aim of this study was to verify the expression of the automatically annotated gene models under various conditions. Another goal was to compare gene expression profiles from different tissues of Heterobasidion irregulare and from mycelium grown on liquid MMN medium, liquid medium amended with lignin or cellulose and on wood.
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:Comparative transcriptome analysis of early interaction events in Scots pine root tissues following challenge with a pathogenic, saprophytic or symbiotic fungus. Seedlings of P. sylvestris (19 days post germination) were transferred to wet, sterile filter paper on Petri-plates. Thereafter, the roots of the seedlings were inoculated with the mycelial homogenate of either Heterobasidion annosum (FP5, P-type) a pathogenic root rot fungus which attacks Norway spruce, Scots pine and broad leaf trees or Laccaria bicolor, an obligate ectomycorrhizal symbiont or Trichoderma aureoviride- an obligate saprotroph. Thereafter, incubated for 30 minutes, during which time some hyphae adhered to the roots. The inoculated seedlings (ten) were then transferred to another wet sterile filter paper placed on 1% water agar in Petri dishes. A second set of moist sterile filter paper was laid over the roots. The region of the Petri-dish containing the roots was covered with aluminium foil and the edges of the plate sealed with parafilm. The seedlings were then incubated for 24 hr under a photoperiod of 16h light at 20 ºC. Control seedlings were âinoculatedâ with sterile distilled water.
