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: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 large pine weevil Hylobius abietis L. is a major forestry pest in 15 European countries, where it is a threat to 3.4 million hectares of forest. A cellular and proteomic analysis of the effect of culture filtrate of three entomopathogenic fungi (EPF) species on the immune system of H. abietis was performed. Injection with Metarhizium anisopliae or Beauvaria bassiana culture showed significantly increased mortality highlighting that EPF culture filtrate has the potential to modulate the insect immune system allowing a subsequent pathogen to proliferate. Injection with EPF culture filtrate was shown to alter the abundance of protease inhibitors, detoxification enzymes, antimicrobial peptides and proteins involved in reception/detection and development in H. abietis larvae. Larvae injected with B. caledonica culture filtrate displayed significant alterations in abundance of proteins involved in cellulytic and other metabolic processes in their haemolymph proteome.
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:We performed a transcriptome analysis of interior spruce (Picea glauca x engelmannii) bark response to weevil (Pissodes strobi) feeding using 21.8K spruce microarray (that contains 21.8 thousand unique transcripts). This microarray study revealed a large rearrangement of the interior spruce bark transcriptome in response to weevil feeding involving differential expression of close to 20% of the studied transcriptome.
Project description:Based on the generation of ESTs, we developed a spruce cDNA microarray composed of 21,843 cDNA elements selected from 12 cDNA libraries representing developmental stages of xylem, phloem, bark and roots, as well as elicitor-treated bark. Clones on the array were selected from a CAP3 assembly of 50,770 hq 3’ ESTs, and were carefully chosen to represent a minimally redundant gene set. Using this array we examined global changes in the transcriptome of Sitka spruce attacked for two days by stem-boring white pine weevils. Differentially expressed genes were determined using three criteria: fold-change between weevil-treated and untreated control > 1.5-fold, P value < 0.05 and Q value < 0.05. After 48 h of weevil feeding, 1,857 (8.5%) microarray elements identified transcripts as up-regulated, compared to 1,374 (6.3%) down-regulated. Keywords: Stress response
Project description:We performed a transcriptome analysis of interior spruce (Picea glauca x engelmannii) bark response to weevil (Pissodes strobi) feeding using 21.8K spruce microarray (that contains 21.8 thousand unique transcripts). This microarray study revealed a large rearrangement of the interior spruce bark transcriptome in response to weevil feeding involving differential expression of close to 20% of the studied transcriptome. RNA was isolated from the bark of interior spruce exposed to weevil feeding and from the bark of untreated trees at three time points (6 hours, 2 days and 2 weeks). Four independent biological replicates were included for treatment and control at each time point. Four hybridizations were performed for treatment and control comparison within each time point (6 hours, 2 days, 2 weeks) and one hybridization was performed for each comparison between time points for both treatment and control (total 18 hybridizations/slides).