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).
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:In the autumn, stems of woody perennials such as forest trees undergo a transition from active growth to dormancy. We used microarray transcriptomic profiling in combination with a proteomics analysis to elucidate processes that occur during this growth-to-dormancy transition in a conifer, white spruce (Picea glauca [Moench] Voss). Several differentially expressed genes were likely associated with the developmental transition that occurs during growth cessation in the cambial zone and the concomitant completion of cell maturation in vascular tissues. Genes encoding for cell wall and membrane biosynthetic enzymes showed transcript abundance patterns consistent with completion of cell maturation, and also of cell wall and membrane modifications potentially enabling cells to withstand the harsh conditions of winter. Several differentially expressed genes were identified that encoded putative regulators of cambial activity, cell development, and of the photoperiodic pathway. Reconfiguration of carbon allocation figured centrally in the tree’s overwintering preparations. For example, genes associated with carbon-based defenses such as terpenoids were downregulated, while many genes associated with proteinbased defenses and other stress mitigation mechanisms were upregulated. Several of these correspond to proteins that were accumulated during the growth-to-dormancy transition, emphasizing the importance of stress protection in the tree’s adaptive response to overwintering. Two year old white spruce (Picea glauca [Moench] Voss) seedlings were used for all experiments, which were conducted as described by El Kayal et al. (2011). Using a complete randomized block design, seedlings were grown in growth chambers under long days (LD; 16h day / 8h night, 20°C, 50 to 60% RH) for 8-10 weeks. Shortly before seedlings were to begin bud formation, the photoperiod was changed to short days (SD; 8h day / 16h night, 20°C, 50 to 60% RH) to induce rapid and synchronous bud formation. This was designated Day 0. Lignified whole stems representing the current year’s growth (microarrays, microscopy) or previous year’s growth (protein analyses) were sampled at 0, 3, 7, 14, 28 and 70 d (10 wk) SD, and immediately frozen in liquid nitrogen. Remaining plants were maintained in SD for an additional 8-15 wk, and then transferred to low temperatures (LT, 2 - 4°C) for 3 to 4 weeks with continuing SD prior to harvest. These are referred to as LT samples.
Project description:The goal is to examine the molecular aspects underpinning somatic embryogenesis (SE) within shoot tissues of adult white spruce trees by conducting transcriptome-wide expression profiling of shoot explants taken from responsive and nonresponsive genotypes.
Project description:In the autumn, stems of woody perennials such as forest trees undergo a transition from active growth to dormancy. We used microarray transcriptomic profiling in combination with a proteomics analysis to elucidate processes that occur during this growth-to-dormancy transition in a conifer, white spruce (Picea glauca [Moench] Voss). Several differentially expressed genes were likely associated with the developmental transition that occurs during growth cessation in the cambial zone and the concomitant completion of cell maturation in vascular tissues. Genes encoding for cell wall and membrane biosynthetic enzymes showed transcript abundance patterns consistent with completion of cell maturation, and also of cell wall and membrane modifications potentially enabling cells to withstand the harsh conditions of winter. Several differentially expressed genes were identified that encoded putative regulators of cambial activity, cell development, and of the photoperiodic pathway. Reconfiguration of carbon allocation figured centrally in the tree’s overwintering preparations. For example, genes associated with carbon-based defenses such as terpenoids were downregulated, while many genes associated with proteinbased defenses and other stress mitigation mechanisms were upregulated. Several of these correspond to proteins that were accumulated during the growth-to-dormancy transition, emphasizing the importance of stress protection in the tree’s adaptive response to overwintering.
Project description:Transcript profiling reveals a molecular signature that distinguishes early versus late time to bud set phenotypes in a white spruce full-sib family.
Project description:Potential link between biotic defense activation and recalcitrance to induction of somatic embryogenesis in shoot primordia from adult trees of white spruce (Picea glauca)