Conifers
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ABSTRACT:
PROVIDER: PRJNA421925 | ENA |
REPOSITORIES: ENA
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Project description:Seasonal cycles of light, temperature and precipitation provide signals that set the timing of gene expression and growth for trees. Conifers possess evergreen needles to sense and respond to year-round external signals. We monitored gene activity in Douglas-fir needles for one year and found that gene expression is dependent on light at daily and annual scales. The majority of rhythmic genes achieve maximum activity +/- 2 hours from sunrise and sunset, and +/- 20 days from the winter and summer solstices. Remarkably, the dormant period is characterized by significant gene activation, with thousands of genes achieving peak activity. This study identifies annual gene rhythms in conifers needles, and provides a framework for identifying genes that respond to other environmental cues. Background: Perennial growth in plants is the product of interdependent cycles of daily and annual stimuli that induce cycles of growth and dormancy. In conifers, needles are the key perennial organ that integrates daily and seasonal signals from light, temperature, and water availability. To understand the relationship between seasonal rhythms and seasonal gene expression responses in conifers, we examined diurnal and circannual needle mRNA accumulation in Douglas-fir (Pseudotsuga menziesii) needles at diurnal and circannual scales. Using mRNA sequencing, we sampled 6.1x10^9 microreads from 19 trees and constructed a de novo pan-transcriptome reference that includes 173,882 tree-derived transcripts. Using this reference, we mapped RNA-Seq reads from 179 samples that capture daily, seasonal, and annual variation. Results: We identified 12,042 diurnally-cyclic transcripts, 9,299 of which showed homology to annotated genes from other plant genomes, including angiosperm core clock genes. Annual analysis revealed 21,225 annually-cyclic transcripts, 17,335 of which showed homology to annotated genes from other plant genomes. The timing of maximum gene expression is associated with light quality at diurnal and photoperiod at annual scales, with two-thirds of transcripts reaching maximum expression +/- 2 hours from sunrise and sunset, and half reaching maximum expression +/- 20 days from winter and summer solstices. Comparison to published microarray-based gene expression studies in spruce (Picea) show that the rank order of expression for 760 putatively orthologous genes was significantly preserved, highlighting the generality of our findings. Conclusions: This finding highlights the extensive annual and seasonal transcriptome variability demonstrated in conifer needles. At these temporal scales, 29% of expressed transcripts showed a significant diurnal rhythm, and 58.7% showed a significant circannual rhythm. Remarkably, thousands of genes reach their annual peak activity during winter dormancy, a time of metabolic stasis. Photoperiod appears to be a dominant driver of annual transcription patterns in Douglas-fir, and these results may be general for predicting rhythmic transcription patterns in emerging gymnosperm models.
2017-01-04 | GSE93067 | GEO
Project description:Seasonal cycles of light, temperature and precipitation provide signals that set the timing of gene expression and growth for trees. Conifers possess evergreen needles to sense and respond to year-round external signals. We monitored gene activity in Douglas-fir needles for one year and found that gene expression is dependent on light at daily and annual scales. The majority of rhythmic genes achieve maximum activity +/- 2 hours from sunrise and sunset, and +/- 20 days from the winter and summer solstices. Remarkably, the dormant period is characterized by significant gene activation, with thousands of genes achieving peak activity. This study identifies annual gene rhythms in conifers needles, and provides a framework for identifying genes that respond to other environmental cues. Background: Perennial growth in plants is the product of interdependent cycles of daily and annual stimuli that induce cycles of growth and dormancy. In conifers, needles are the key perennial organ that integrates daily and seasonal signals from light, temperature, and water availability. To understand the relationship between seasonal rhythms and seasonal gene expression responses in conifers, we examined diurnal and circannual needle mRNA accumulation in Douglas-fir (Pseudotsuga menziesii) needles at diurnal and circannual scales. Using mRNA sequencing, we sampled 6.1x10^9 microreads from 19 trees and constructed a de novo pan-transcriptome reference that includes 173,882 tree-derived transcripts. Using this reference, we mapped RNA-Seq reads from 179 samples that capture daily, seasonal, and annual variation. Results: We identified 12,042 diurnally-cyclic transcripts, 9,299 of which showed homology to annotated genes from other plant genomes, including angiosperm core clock genes. Annual analysis revealed 21,225 annually-cyclic transcripts, 17,335 of which showed homology to annotated genes from other plant genomes. The timing of maximum gene expression is associated with light quality at diurnal and photoperiod at annual scales, with two-thirds of transcripts reaching maximum expression +/- 2 hours from sunrise and sunset, and half reaching maximum expression +/- 20 days from winter and summer solstices. Comparison to published microarray-based gene expression studies in spruce (Picea) show that the rank order of expression for 760 putatively orthologous genes was significantly preserved, highlighting the generality of our findings. Conclusions: This finding highlights the extensive annual and seasonal transcriptome variability demonstrated in conifer needles. At these temporal scales, 29% of expressed transcripts showed a significant diurnal rhythm, and 58.7% showed a significant circannual rhythm. Remarkably, thousands of genes reach their annual peak activity during winter dormancy, a time of metabolic stasis. Photoperiod appears to be a dominant driver of annual transcription patterns in Douglas-fir, and these results may be general for predicting rhythmic transcription patterns in emerging gymnosperm models.
2017-01-04 | GSE93066 | GEO
Project description:MicroRNAs (miRNAs) are small noncoding regulatory RNAs that play key roles in the process of plant development. To date, extensive studies of miRNAs have been performed in a few model plants, but few efforts have focused on small RNAs in conifers because of the lack of reference sequences for these enormous genomes. In this study, Solexa sequencing of three small RNA libraries obtained from dormant, reactivating, and active vascular cambium in Chinese fir samples identified 76 known miRNAs from 27 miRNA families and 18 new potential miRNAs, of which 15 novel miRNA precursors were validated by RT-PCR and sequencing. More than half of these novel miRNAs displayed stage-specific expression patterns in the vascular cambium. Furthermore, analyzing the 103 miRNAs and their predicted targets indicated that 30% of miRNAs appeared to negatively regulate their targets, of which 4 target genes involved in the regulation of cambial cell division were validated via RNA ligase-mediated rapid amplification of 5’ cDNA ends (RLM 5’-RACE). Interestingly, miRNA156 and miRNA172 may regulate the phase transition in vascular cambium from dormancy to active growth. These results provide new insights into the important regulatory functions of miRNAs in vascular cambium development and wood formation in conifers.
2015-04-07 | GSE53933 | GEO
Project description:Analysis of Paulownia tomentosa cambial tissues at gene expression level. The hypothesis tested in the present study was that miRNAs can regulate the development of the vascular cambium.The results provide new insights into the important regulatory functions of miRNAs in vascular cambium development and wood formation in conifers.
2021-01-17 | GSE109323 | GEO
Project description:Cold acclimation in conifers is a complex process, the timing and extent of which reflects local adaptation and varies widely along latitudinal gradients for many temperate and boreal tree species. In spite of their ecological and economic importance, little is known about the global changes in gene expression that accompany autumn cold acclimation in conifers. Using three populations of Sitka spruce (Picea sitchensis) spanning the species range, and a Picea cDNA microarray with 21,840 unique elements, we monitored within and among-population gene expression during the fall. Microarray data were validated for selected genes using real-time PCR. Similar numbers of genes were significantly two-fold upregulated (1,257) and downregulated (967) between late summer and early winter. Among those upregulated were dehydrins, pathogenesis-related/antifreeze genes, carbohydrate and lipid metabolism genes, and genes involved in signal transduction and transcriptional regulation. Among-population microarray hybridizations at early and late autumn time points revealed substantial variation in the autumn transcriptome, some of which may reflect local adaptation. Our results demonstrate the complexity of cold acclimation in conifers, highlight similarities and differences to cold tolerance in annual plants, and provide a solid foundation for functional and genetic studies of this important adaptive process in conifers. Keywords: Time course
2008-06-01 | GSE8370 | GEO
Project description:Comparative genomics in conifers
| PRJEB64176 | ENA
Project description:Wood in conifers is mainly composed of tracheids. Some taxa, such as Pinus, present tracheids also in the rays, but are axial tracheids which constitute the vast majority of secondary xylem. Nevertheless, radial and axial parenchyma surrounding constitutive and traumatic resin ducts is known to serve as crucial reserve storage. These reserves are mobilized in response to traumatism, insect and pathogen attacks and defoliation, allowing the synthesis of resin, healing and, in few taxa, even resprouting. However, due to the low proportion of parenchymatic cells in secondary xylem relevant genes involved in their differentiation may have been missed in studies of transcriptomics of conifer wood formation. In this study we have used Pinus canariensis as a model species, given its comparatively high proportion of axial parenchyma. We have prepared two normalized libraries from its cambial zone, covering early- and late-wood differentiation. We have de novo assembled a transcriptome, and have analyzed the transcriptional profiles during the growing season, getting a more complete picture of wood formation in conifers. SUBMITTER_CITATION: Chano, V., López de Heredia, U., Collada, C., et al. (2017). Transcriptomic analysis of juvenile wood formation during the growing season in Pinus canariensis. Holzforschung, 0(0), pp. -. Retrieved 8 Aug. 2017, from doi:10.1515/hf-2017-0014
2016-09-01 | GSE82217 | GEO