Project description:Global transcriptional analysis of loblolly pine (Pinus taeda L.) is challenging due to limited molecular tools. PtGen2, a 26,496 feature cDNA microarray, was fabricated and used to assess drought-induced gene expression in loblolly pine propagule roots. Statistical analysis of differential expression and weighted gene correlation network analysis were used to identify drought-responsive genes and further characterize the molecular basis of drought tolerance in loblolly pine.
Project description:Microarray analysis and scale-free gene networks identify candidate regulators in drought-stressed roots of loblolly pine (P. taeda L.).
Project description:Sirex noctilio F., a Eurasian horntail woodwasp recently introduced into North America, oviposits in pines and other conifers and in the process spreads a phytopathogenic fungus that serves as a food source for its larvae. During oviposition the woodwasp also deposits a mucus produced in its acid (venom) gland that alters pine defense responses and facilitates infection by the fungus. A 26,496-feature loblolly pine cDNA microarray was used to survey gene expression of pine tissue responding to S. noctilio venom. Six genes were selected for further assessment by qRT-PCR, including one that encoded an apparent PR-4 protein and another that encoded a thaumatin-like protein. Expression of both was strongly induced in response to venom, while expression of an apparent actin gene (ACT1) was stable in response to the venom. The pattern of gene response was similar in Pinus taeda L. and P. radiata D. Don, but the magnitude of response in P. radiata was significantly stronger for each of the induced genes. The magnitude of biomarker gene response to venom also varied according to genotype within these two species. The qRT-PCR assay was used to demonstrate that the primary bioactive component in S. noctilio venom is a polypeptide.
Project description:Sirex noctilio F., a Eurasian horntail woodwasp recently introduced into North America, oviposits in pines and other conifers and in the process spreads a phytopathogenic fungus that serves as a food source for its larvae. During oviposition the woodwasp also deposits a mucus produced in its acid (venom) gland that alters pine defense responses and facilitates infection by the fungus. A 26,496-feature loblolly pine cDNA microarray was used to survey gene expression of pine tissue responding to S. noctilio venom. Six genes were selected for further assessment by qRT-PCR, including one that encoded an apparent PR-4 protein and another that encoded a thaumatin-like protein. Expression of both was strongly induced in response to venom, while expression of an apparent actin gene (ACT1) was stable in response to the venom. The pattern of gene response was similar in Pinus taeda L. and P. radiata D. Don, but the magnitude of response in P. radiata was significantly stronger for each of the induced genes. The magnitude of biomarker gene response to venom also varied according to genotype within these two species. The qRT-PCR assay was used to demonstrate that the primary bioactive component in S. noctilio venom is a polypeptide. Reference design. Two condition experiment, two time points each compared to a common reference. Two biological replicates, two technical replicates, 12 slides total, duplicate/re-scanned images submitted for each slide.
Project description:The significant morphological differences observed during embryo development in angiosperms and gymnosperms are expected to be the result of a differential control of gene expression. We used a loblolly pine (Pinus taeda) cDNA microarray to analyze global transcriptional changes along zygotic embryogenesis in maritime pine (Pinus pinaster). A time-course analysis of the data obtained from the five embryo developmental groups used in this study led to the identification of 4,645 genes whose expression varied along P. pinaster embryogenesis. These transcripts were clustered into six distinct expression profiles. The grouping of these profiles in early, mid-embryogenesis and embryo maturation, according to the developmental period where most of the sequences were up-regulated, evidenced that characteristic transcriptional changes are associated to each developmental period. The application of a cut-off value of 1.95-fold change led to the identification of 1,838 differentially expressed transcripts that were categorized by biological process. Metabolism, interaction with the environment, oxidation-reduction and transport were some of the most represented categories. During early embryogenesis genes putatively involved in phytohormone-mediated signaling were identified, whereas in middle stages the overrepresented genes could be associated with cotyledon formation and induction of somatic embryogenesis. Genes associated with the synthesis of storage products were up-regulated in the latest stages of pine embryo development. It was also during this developmental period that the largest number of sequences putatively encoding transcription factors was identified.
Project description:The significant morphological differences observed during embryo development in angiosperms and gymnosperms are expected to be the result of a differential control of gene expression. We used a loblolly pine (Pinus taeda) cDNA microarray to analyze global transcriptional changes along zygotic embryogenesis in maritime pine (Pinus pinaster). A time-course analysis of the data obtained from the five embryo developmental groups used in this study led to the identification of 4,645 genes whose expression varied along P. pinaster embryogenesis. These transcripts were clustered into six distinct expression profiles. The grouping of these profiles in early, mid-embryogenesis and embryo maturation, according to the developmental period where most of the sequences were up-regulated, evidenced that characteristic transcriptional changes are associated to each developmental period. The application of a cut-off value of 1.95-fold change led to the identification of 1,838 differentially expressed transcripts that were categorized by biological process. Metabolism, interaction with the environment, oxidation-reduction and transport were some of the most represented categories. During early embryogenesis genes putatively involved in phytohormone-mediated signaling were identified, whereas in middle stages the overrepresented genes could be associated with cotyledon formation and induction of somatic embryogenesis. Genes associated with the synthesis of storage products were up-regulated in the latest stages of pine embryo development. It was also during this developmental period that the largest number of sequences putatively encoding transcription factors was identified. Pine immature zygotic embryos were pooled into five different developmental groups according to the collection date (Day0; Day5; Day11; Day15 and Day25). A common reference design was used. Total RNA was extracted from each sample. Three extractions were prepared per sample (biological replicates). A defined ammount from each RNA sample was pooled to use as reference. Messenger RNA was amplified for both test samples and reference. These were hybridized together in two separate experiments (technical replicates). In total, 30 slides were analyzed.