Many species of Populus, particularly cottonwoods of sections Aigeiros and Tacamahaca, remain recalcitrant to genetic transformation. We demonstrate that transgenic trees can be readily produced in several poplar genotypes using wild-type Agrobacterium rhizogenes. Hairy roots were produced in a variety of clones that included Populus trichocarpa Torr. & A. Gray,...
Overexpression of the bacterio-opsin (bO) gene in tobacco had previously been shown to induce hypersensitiveresponse- like lesions, increase viral and bacterial disease resistance, and stimulate pathogenesis-related gene expression. To see if this gene enhanced resistance to fungal pathogens of poplar, we generated a total of 35 transgenic lines in two...
We studied xylem anatomy and hydraulic architecture in 14 transgenic insertion events and a control line of hybrid poplar (Populus spp.) that varied in lignin content. Transgenic events had different levels of down‐regulation of two genes encoding 4‐coumarate:coenzyme A ligase (4CL). Two‐year‐old trees were characterized after growing either as free‐standing...
Of 14 transgenic poplar genotypes (Populus tremula × Populus alba) with antisense 4-coumarate:coenzyme A ligase that were grown in the field for 2 years, five that had substantial lignin reductions also had greatly reduced xylem-specific conductivity compared with that of control trees and those transgenic events with small reductions in...
Transgenic down-regulation of the Pt4CL1 gene family encoding 4-coumarate:coenzyme A ligase (4CL) has been reported as a
means for reducing lignin content in cell walls and increasing overall growth rates, thereby improving feedstock quality for
paper and bioethanol production. Using hybrid poplar (Populus tremula 3 Populus alba), we applied this...
Semidwarfism has been used extensively in row crops and horticulture to promote yield, reduce lodging, and improve harvest index, and it might have similar benefits for trees for short-rotation forestry or energy plantations, reclamation, phytoremediation, or other applications. We studied the effects of the dominant semidwarfism transgenes GA Insensitive (GAI)...
•Plant population genomics informs evolutionary biology, breeding, conservation and bioenergy feedstock development. For example, the detection of reliable phenotype–genotype associations and molecular signatures of selection requires a detailed knowledge about genome-wide patterns of allele frequency variation, linkage disequilibrium and recombination.
•We resequenced 16 genomes of the model tree Populus trichocarpa...
Background: DNA cytosine methylation is an epigenetic modification that has been implicated in many biological processes. However, large-scale epigenomic studies have been applied to very few plant species, and variability in methylation among specialized tissues and its relationship to gene expression is poorly understood.
Results: We surveyed DNA methylation from...
Comparative analysis of multiple angiosperm genomes has implicated gene duplication in the expansion and diversification of many gene families. However, empirical data and theory suggest that whole-genome and small-scale duplication events differ with respect to the types of genes preserved as duplicate pairs. We compared gene duplicates resulting from a...
Epigenetic variation is likely to contribute to the phenotypic plasticity and adaptative
capacity of plant species, and may be especially important for long-lived
organisms with complex life cycles, including forest trees. Diverse environmental
stresses and hybridization/polyploidization events can create reversible heritable
epigenetic marks that can be transmitted to subsequent generations...