Project description:Embolism and the refilling of xylem vessels are intrinsic to the ability of plants to handle the transport of water under tension. While the formation of an embolized vessel is an abiotic process, refilling against the pressure gradient requires biological activity to provide both the energy and the water needed to restore xylem transport capacity. We used microarrays to analyze the global transcriptome response of xylem parenchyma cells after embolism formation or infiltration of xylem tissue with sucrose solution. Plants subjected to artificial embolism treatment (ET), to sucrose infiltration treatment (ST), and controls (C) were selected for RNA extraction and hybridization on Affymetrix microarrays. Embolism was artificially induced through air-injection into the stems of the ET plants, while ST plants were exposed to osmotic stress by adding sucrose to the growing solution. Woody stems were respectively collected 90 minutes following the injection and after 90 minutes of exposure to sucrose.
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:Our analysis provides a comprehensive picture of how P. trichocarpa responds to drought stress at physiological and transcriptome levels which may help to understand molecular mechanisms associated with drought response and could be useful for genetic engineering of woody plants. Drought stress treatment was performed dividing P. trichocarpa plants into the well-watered (WW) group (soil volumetric water content of 40â45 %) and the water-limited group (soil volumetric water content of 10â15 %). Two cDNA libraries constructed separately from the WW and WL groups were subjected to high-throughput Illumina sequencing.
Project description:PtrHSFB3-1 and PtrMYB092 are xylem specific genes in xylem of P. trichocarpa, and their expression levels are down regulated most significantly in tension wood. These two transcription factors were transiently overexpressed in stem differentiating xylem (SDX) of P. trichocarpa , and transcriptomic sequencing was performed to identify the regulatory effects of the two transcription factors on wood formation related genes.
Project description:We used the stem cross-sections of P. trichocarpa and our recently developed laser capture microdissection (LCM) to collect fibers, vessels, and a combination of 3 cell types (fibers + vessels + rays). Total RNA from the three samples was isolated, amplified, and analyzed by full-transcriptome RNA-sequencing. The sequencing reads were mapped to the P. trichocarpa genome.
Project description:We treated 6 month Populus trichocarpa by bending for 0, 3, and 7 days to see effects of bending treatment on wood formation at transcript level
Project description:Illumina HiSeq2000 technology was used to generate mRNA profiles from the ectomycorrhizal fungi Laccaria bicolor colonizing roots of Populus trichocarpa. Samples were taken after 3 months of contact in order to identify mycorrhiza-regulated transcripts. 100bp reads were generated and aligned to the Populus trichocarpa (http://www.phytozome.net/poplar.php) reference genome.
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:We studied the changes that occur in gene transcription and the biosynthesis of cell-wall-related compounds during xylogenesis in Populus trichocarpa pioneer roots and stems. Transcriptional profiling was conducted with the use of microarrays to identify genes involved in xylem formation. Pioneer roots were examined in segments corresponding to their developmental stage: apical meristem (PR1), primary development (PR2), and secondary development (PR3). Comparative segments were used to analyze xylogenesis in stems: apical meristem with primary development (PS1), secondary development (PS2), and isolated secondary xylem (PS3). Results indicated that only approximately 10% of the genes that were identified to be differentially expressed during xylogenesis were common to both pioneer roots and stems. Despite the dissimilarity in gene expression, however, many fundamental mechanisms were similar, e.g. the pattern of expression of genes involved in the biosynthesis of cell wall proteins, polysaccharides and lignins. While hemicellulose degradation was typical for stems, possibly due to the intensive level of cell wall lignification. Our study is the first to conduct a comprehensive analysis, at the structural and molecular level, of xylogenesis, and clearly reveals the great complexity of molecular mechanisms underlying cell wall formation and modification during xylogenesis.
Project description:The heat shock response continues to be layered with additional complexity as interactions and cross-talk among heat shock proteins, the reactive oxygen network and hormonal signaling are discovered. However, comparative analyses exploring variation in each of these processes among species remains relatively unexplored. In controlled environment experiments, photosynthetic response curves were conducted from 22 °C to 42 °C and indicated that temperature optimum of light saturated photosynthesis was greater for Glycine max relative to Arabidopsis thaliana or Populus trichocarpa. Transcript profiles were taken at defined states along the temperature response curves and inferred pathway analysis revealed species-specific variation in the abiotic stress and the minor carbohydrate raffinose/galactinol pathways. A weighted gene co-expression network approach was used to group individual genes into network modules linking biochemical measures of the antioxidant system to leaf-level photosynthesis among P. trichocarpa, G. max and A. thaliana. Network enabled results revealed an expansion in the G. max HSP17 protein family and divergence in the regulation of the antioxidant and heat shock module relative to P. trichocarpa and A. thaliana. These results indicate that although the heat shock response is highly conserved, there is considerable species-specific variation in its regulation.