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:Using 21K spruce microarray (that contains 21.8 thousand unique transcripts) we performed analysis of the transcriptome response of lodgepole pine (Pinus contorta) inoculated with the mountain pine beetle (Dendroctonus ponderosae) vectored fungal pathogen Grosmannia clavigera or treated with wounding. This microarray analysis revealed large transcriptome reorganization with close to 2000 transcripts (10% of the studied transcriptome) differentially expressed within two weeks of treatment, with the wounding response affecting close to 2% of the lodgepole pine transcriptome. RNA was isolated from the bark of lodgepole pine inoculated with Grosmannia clavigera, treated with wounding, or untreated control for three time points (6h, 2days and 2 weeks). Three independent biological replicates were included for each treatment and each time point. Three hybridizations were performed for each comparison of different treatments (fungal, wounding, control) within each time point (6 hours, 2 days, 2 weeks) and one hybridization was performed for the comparison of the same treatments between time points (total 36 hybridizations/slides).
Project description:White pine weevil is a major pest of conifers in North America, especially for Spruce trees. Constitutive defenses are important in understanding defense mechanisms because they constitute the initial barrier to attacks by weevils and other pests. Resistant and susceptible trees exhibit constitutive differences in spruce. To improve our knowledge of their genetic basis, we compared the constitutive expression levels of 17,825 genes between 20 resistant and 20 susceptible trees in interior spruce (Picea glauca). Twenty hybridizations were performed to compare untreated bark of resistant and susceptible trees.RNA isolated from each of the 20 individual untreated resistant trees was compared directly against the 20 individual untreated susceptble trees using two hybridizations with a dye flip for each tree pair.
Project description:Bark beetles (Coleoptera: Scolytinae) are pests of many forests around the world. The mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins, is a significant pest of western North American pine forests. The MPB is able to overcome the defences of pine trees through pheromone-assisted aggregation that results in a mass attack of host trees. These pheromones, both male and female produced, are believed to be biosynthesized in the midgut and/or fat body of these insects. We have used transcriptomics (RNA-seq) to identify transcripts differentially expressed between sexes and between tissues, with juvenile hormone III treatment, which is known to induce pheromone biosynthesis.
Project description:The bark represents the outer protective layer of trees. It contains high concentrations of antimicrobial extractives, in addition to regular wood polymers. It represents a huge underutilized side stream in forestry, but biotechnological valorization is hampered by a lack of knowledge on microbial bark degradation. Many fungi are efficient lignocellulose degraders, and here, spruce bark degradation by five species, Dichomitus squalens, Rhodonia placenta, Penicillium crustosum, Trichoderma sp. B1, and Trichoderma reesei, was mapped, by continuously analyzing chemical changes in the bark over six months. The study reveals how fungi from different phyla degrade bark using diverse strategies, regarding both wood polymers and extractives, where toxic resin acids were degraded by Basidiomycetes but unmodified/tolerated by Ascomycetes. Proteome analyses of the white-rot D. squalens revealed several proteins, with both known and unknown functions, that were specifically upregulated during growth on bark. This knowledge can accelerate improved utilization of an abundant renewable resource.
Project description:Compression (CW) and opposite wood (OW) are formed in the uniderside and upperside of conifer branches respectively in response to gravity stress. We investigated genes differentially transcribed between the underside and upside of radiate pine branches using cDNA microarrays with a view to plant gravitropism. Six trees with well-developed branches were selected from a radiata pine commercial plantation (aged 13 years) located at Bondo, NSW, Australia (35º 16' 44.04 S, 148º 26' 54.66 E). The largest branch from each tree was further selected for sampling, including three branches sampled in April 2007 (autumn in Bondo) and three sampled in October 2007 (spring). Bark was removed from the base part (about 10 cm in length) of each branch. Developing xylem tissues were scraped from the exposed upperside and underside surface respectively with a sharp chisel. Samples were immediately placed into 50 ml BD FalconTM tubes filled with liquid nitrogen. Gene expression in the underside and upperside of branches was compared using radiata pine cDNA microarrays.
Project description:Using 21K spruce microarray (that contains 21.8 thousand unique transcripts) we performed analysis of the transcriptome response of lodgepole pine (Pinus contorta) inoculated with the mountain pine beetle (Dendroctonus ponderosae) vectored fungal pathogen Grosmannia clavigera or treated with wounding. This microarray analysis revealed large transcriptome reorganization with close to 2000 transcripts (10% of the studied transcriptome) differentially expressed within two weeks of treatment, with the wounding response affecting close to 2% of the lodgepole pine transcriptome.
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:The periderm of trees produces cork cells, whose cell walls are modified with suberin. We compared the transcriptome of outer bark (cork) vs inner bark (control containing secondary phloem and vacular meristem) to infer genes related to suberim metabolism.