Project description:To obtain genes expression in different parts of 84k poplar stems, transcriptome sequencing was performed using Illumina Novaseq 6000 second-generation sequencing platform from Shanghai BIOZERON Co. Ltd (www.biozeron.com). Selecte three stem segments of plants REPEAT 1, 2 and 3 with good and similar growth to use: 2nd-3rd internodes (poplar stem top: PST1, PST2, PST3); 9th-10th internodes (poplar stem middle: PSM1, PSM2, PSM3); 14th-15th internodes (poplar stem bottom: PSB1, PSB2, PSB3). [Or the three repeating organisms are also called poplar A, B, C. From top to bottom, the three parts of the stem are also called stem 1, 2, 3.]
Project description:Here we applied a novel approach to isolate nuclei from complex plant tissues (https://doi.org/10.1371/journal.pone.0251149), to dissect the transcriptome profiling of the hybrid poplar (Populus tremula × alba) vegetative shoot apex at single-cell resolution.
Project description:Plants transition through juvenile and adult phases of vegetative development in a process known as vegetative phase change (VPC). In poplars (genus Populus) the differences between these stages are subtle, making it difficult to determine when this transition occurs. Previous studies of VPC in poplars have relied on plants propagated in vitro, leaving the natural progression of this process unknown. We examined developmental morphology of seed-grown and in vitro derived Populus tremula × alba (clone 717-1B4), and compared the phenotype of these to transgenics with manipulated miR156 expression, the master regulator of VPC. In seed-grown plants, most traits changed from node-to-node during the first 3 months of development but remained constant after node 25. Many traits remained unchanged in clones over-expressing miR156, or were enhanced when miR156 was lowered, demonstrating their natural progression is regulated by the miR156/SPL pathway. The characteristic leaf fluttering of Populus is one of these miR156-regulated traits. Vegetative development in plants grown from culture mirrored that of seed-grown plants, allowing direct comparison between plants often used in research and those found in nature. These results provide a foundation for further research on the role of VPC in the ecology and evolution of this economically important genus.
Project description:Poplar 84K (Populus alba x P. tremula var. glandulosa) is a fast-growing poplar hybrid. Originated in South Korea, this hybrid has been extensively cultivated in northern China. Due to the economic and ecological importance of this hybrid and high transformability, we now report the de novo sequencing and assembly of a male individual of poplar 84K using PacBio and Hi-C technologies. The final reference nuclear genome (747.5?Mb) has a contig N50 size of 1.99?Mb and a scaffold N50 size of 19.6?Mb. Complete chloroplast and mitochondrial genomes were also assembled from the sequencing data. Based on similarities to the genomes of P. alba var. pyramidalis and P. tremula, we were able to identify two subgenomes, representing 356?Mb from P. alba (subgenome A) and 354?Mb from P. tremula var. glandulosa (subgenome G). The phased assembly allowed us to detect the transcriptional bias between the two subgenomes, and we found that the subgenome from P. tremula displayed dominant expression in both 84K and another widely used hybrid, P. tremula x P. alba. This high-quality poplar 84K genome will be a valuable resource for poplar breeding and for molecular biology studies.
Project description:Microarray technology was used to assess transcriptome changes in poplar (Populus alba L.) under a realistic simulation of increased UV-B radiation. Plants were UV-Bbe (UV-B biologically effective radiation) supplemented with a dose of 6 kJ/m2/day for 12 hours per day and allowed to recover during the night. Poplar plants were UV-B treated using a refined controlled environment able to guarantee a realistic simulation of natural conditions, especially for light parameters such as presence of background UV-B radiation for control plants and balanced PAR/UV-A/UV-B ratio. A time course experiment was planned to look both at the rapid and delayed response of poplar to UVB; two time points after 3 h (T3h) and 30 h (6th hour of the third day of treatment, T30h) were considered. 4 independent biological replicates were analysed for each time point. Competitive hybridisations were carried out using the PICME 28K microarray. Keywords: Time course experiment, stress response
Project description:A foundational study assessed effects of biochemical pathway introduction into poplar to produce eugenol, chavicol, p-anol, isoeugenol and their sequestered storage products, from potentially available substrates, coniferyl and p-coumaryl alcohols. At the onset, it was unknown whether significant carbon flux to monolignols vs. other phenylpropanoid (acetate) pathway metabolites would be kinetically favoured. Various transgenic poplar lines generated eugenol and chavicol glucosides in ca. 0.45% (~0.35 and ~0.1%, respectively) of dry weight foliage tissue in field trials, as well as their corresponding aglycones in trace amounts. There were only traces of any of these metabolites in branch tissues, even after ~4-year field trials. Levels of bioproduct accumulation in foliage plateaued, even at the lowest introduced gene expression levels, suggesting limited monolignol substrate availability. Nevertheless, this level still allows foliage collection for platform chemical production, with the remaining (stem) biomass available for wood, pulp/paper and bioenergy product purposes. Several transformed lines displayed unexpected precocious flowering after 4-year field trial growth. This necessitated terminating (felling) these particular plants, as USDA APHIS prohibits the possibility of their interacting (cross-pollination, etc.) with wild-type (native plant) lines. In future, additional biotechnological approaches can be employed (e.g. gene editing) to produce sterile plant lines, to avoid such complications. While increased gene expression did not increase target bioproduct accumulation, the exciting possibility now exists of significantly increasing their amounts (e.g. 10- to 40-fold plus) in foliage and stems via systematic deployment of numerous 'omics', systems biology, synthetic biology and metabolic flux modelling approaches.