Project description:Populus deltoides and Populus trichocarpa were exposed to either ambient air or an acute ozone exposure of 200 ppb for 9 hrs and ozone response was profiled for each genotype by hybridising control against ozone-exposed samples per genotype. Keywords: stress response, genotype comparrison, ozone exposure
Project description:Microarray expression profiling was carried out in poplar leaves upon infection with rust in order to identify genes expressed during tree defense response. For this purpose, we inoculated detached leaves of the interamerican hybrid poplar Populus trichocarpa x Populus deltoides 'Beaupré' grown in greenhouse with spores of avirulent strain 93ID6 of the pathogenic rust fungus Melampsora larici-populina (incompatible interaction, I48). Besides, we mock-inoculated 'Beaupré' leaves with water (control condition, T48). Detached leaves were maintained in vitro in controled conditions to allow fungal infection and colonization of plant tissue. Leaves were sampled 48 hours post-inoculation after that the fungus attempt to penetrate plant cells in mesophyll. Competitive hybridization between transcripts of incompatible interaction (I48) and control condition (T48) was done on Populus PICME 28K cDNA microarray. Keywords: Time-course infection of plant tissue, defense response, cDNA microarray
Project description:TA inhibits cellulose synthesis but its actual mode of action is unknown. Addition of TA to hybrid poplar (Populus trichocarpa x Populus deltoides) cell suspensions can activate a cellular program leading to cell death. In contrast, it is possible to habituate hybrid poplar cell cultures to grow in the presence of TA levels that would normally induce cell death. This habituation was performed by adding increasing levels of TA to cell cultures at the time of subculture over a period of 12 months. TA-habituated cells were then cultured in the absence of TA for more than 18 months. These cells displayed a reduced size and growth compared to control cells and had fragmented vacuoles filled with electron-dense material. Habituation to TA was associated with changes in the cell wall composition, with a reduction in cellulose and an increase in pectin levels. Remarkably, high level of resistance to TA was maintained in TA-habituated cells even after being cultured in the absence of TA. Moreover, these cells exhibited enhanced resistance to two other inhibitors of cellulose biosynthesis, dichlobenil and isoxaben. Analysis of gene expression in TA-habituated cells using Affymetrix GeneChip Poplar Genome Array revealed that durable resistance to TA is associated with a major and complex reprogramming of gene expression implicating processes such as cell wall synthesis and modification, lignin and flavonoid synthesis, as well as DNA and chromatin modifications. Experiment Overall Design: Each sample was taken from an individual flask of control cells or TA-habituated resistant cells grown without the toxin for 18 months (TA(-)hab cells) that had grown for 5 d after subculture. Six arrays were hybridized, representing 3 arrays per cell type.
Project description:cDNA macroarray expression profiling was carried out in poplar leaves upon infection with rust in order to identify genes expressed during tree defense response. For this purpose, we inoculated detached leaves of the interamerican hybrid poplar Populus trichocarpa x Populus deltoides 'Beaupré' grown in greenhouse either with spores of avirulent strain 93ID6 (incompatible interaction, I) or spores of virulent strain 98AG31 (compatible interaction, C) of the pathogenic rust fungus Melampsora larici-populina. Besides, we mock-inoculated 'Beaupré' leaves with water (control condition, T). Detached leaves were maintained in vitro in controled conditions to allow fungal infection and colonization of plant tissue. Leaves were sampled at 12, 24 and 48 hours post-inoculation (hpi) in a time-course experiment before (12 hpi) and after (24 and 48 hpi) that the fungus attempt to penetrate plant cells in mesophyll. Keywords: Plant tissue infection, Plant defense response, cDNA macroarray
Project description:A microarray analysis of whole-genome gene expression in leaves was carried out in a (Populus trichocarpa X Populus deltoides) X Populus deltoides pseudo-backcross pedigree. Genetic variation in gene expression was quantified for 55,793 predicted gene models based on a single probe per gene. Resultant data contributed to the analysis of the genetic architecture of gene expression in leaves of Populus.
Project description:The majority of trees live in association with symbiotic fungi, which facilitate their access to soil nutrients. The ectomycorrhizal symbiosis represents a complex biological system involving multifaceted interactions between the two partners. The establishment of the symbiosis depends on various conditions (e.g. climate), but also on the genetic traits of the partners. To evaluate the impact of the genetic predisposition on the development and functioning of ectomycorrhizas, we compared the transcriptome of roots from Populus trichocarpa and Populus deltoides colonized with Laccaria bicolor. The Populus whole-genome expression array version 2.0 (S. DiFazio, A. Brunner, P. Dharmawardhana, and K. Munn, unpublished data) manufactured by NimbleGen Systems Limited (Madison, WI) contains in duplicates three independent, non-identical, 60-mer probes per whole gene model plus control probes and labeling controls. Included in the microarray are 65,965 probe sets corresponding to 55,970 gene models predicted on the P.trichocarpa genome sequence version 1.0 and 9,995 aspen cDNA sequences (Populus tremula, Populus tremuloides, and P. tremula x P. tremuloides). NimbleGen whole genome microarray analyses were performed in triplicate as per manufacturer's instructions. We carried out six hybridizations (NimbleGen) with samples derived from Populus trichocarpa and Populus deltoides mycorrhizal root tips. Three samples (biological replicates) originated from Populus trichocarpa (GSM648401, GSM648403, GSM648405) and three biological replicates from Populus deltoides (GSM648408, GSM648411, GSM648414). cDNA was synthesized using CLONTECH Super Smart cDNA Synthesis kit containing an amplification step on the cDNA level. All samples were labeled with Cy3.
Project description:A microarray analysis of whole-genome gene expression in roots was carried out in a (Populus trichocarpa X Populus deltoides) X Populus deltoides pseudo-backcross pedigree. Genetic variation in gene expression was quantified for 55,793 predicted gene models based on a single probe per gene. Resultant data contributed to the analysis of the genetic architecture of gene expression in roots of Populus.
Project description:Populus deltoides and Populus trichocarpa were exposed to either ambient air or an acute ozone exposure of 200 ppb for 9 hrs and ozone response was profiled for each genotype by hybridising control against ozone-exposed samples per genotype. Keywords: stress response, genotype comparrison, ozone exposure RNA was extracted from the fifth leaf below the first fully unfurled leaf for each plant. Control and ozone-exposed plants were then randomly paired for hybridisation.
Project description:A microarray analysis of whole-genome gene expression and single feature polymorphism in a (Populus trichocarpa X Populus deltoides) X Populus deltoides pseudo-backcross pedigree. Genetic variation in gene expression was quantified for 55,793 predicted gene models based on a single probe per gene. Concurrently, sequence-level polymorphism was analyzed based on dedicated probes identified in a pilot study comprised of the two parent genotypes (GPL7169). Resultant data contributed to a high density genetic map and to analysis of the genetic architecture of gene expression in Populus. Keywords: Genetic analysis of gene expression and polymorphism, eQTL