A molecular framework for seasonal growth-dormancy regulation in perennial plants.

The timing of the onset and release of dormancy impacts the survival, productivity and spatial distribution of temperate horticultural and forestry perennials and is mediated by at least three main regulatory programs involving signal perception and processing by phytochromes (PHYs) and PHY-interacting transcription factors (PIFs). PIF4 functions as a key regulator of plant growth in response to both external and internal signals. In poplar, the expression of PIF4 and PIF3-LIKE1 is upregulated in response to short days, while PHYA and PHYB are not regulated at the transcriptional level.

Novel aspects of transcriptional regulation in the winter survival and maintenance mechanism of poplar.

Temperate woody plants have developed sophisticated winter survival and maintenance mechanisms that enable them to adapt rapidly to the annual cycle of environmental changes. Here, we demonstrate notable aspects of the transcriptional regulation adopted by poplar in winter/dormancy, employing biochemical and whole transcriptome analysis, and showing high levels of transcriptional activity in a broad spectrum of genes during the dormancy period. A total of 3237 probe sets upregulated more than threefold in winter/dormancy stems over summer/active-growth stems were identified.

Transcriptional profiles of the annual growth cycle in Populus deltoides.

Cycling between vegetative growth and dormancy is an important adaptive mechanism in temperate woody plants. To gain insights into the underlying molecular mechanisms, we carried out global transcription analyses on stem samples from poplar (Populus deltoides Bartr. ex Marsh.

Seasonal changes in gene expression at the sapwood-heartwood transition zone of black locust (Robinia pseudoacacia) revealed by cDNA microarray analysis.

Heartwood is a determining factor of wood quality and understanding the biology of heartwood may allow us to control its formation. Heartwood formation is a form of senescence that is accompanied by a variety of metabolic alterations in ray parenchyma cells at the sapwood-heartwood transition zone. Although senescence has been studied at the molecular level with respect to primary growth, the cell maturation and death events occurring during heartwood formation have been difficult to study because of their location and timing.

Novel gene expression profiles define the metabolic and physiological processes characteristic of wood and its extractive formation in a hardwood tree species, Robinia pseudoacacia.

Wood is of critical importance to humans as a primary feedstock for biofuel, fiber, solid wood products, and various natural compounds including pharmaceuticals. The trunk wood of most tree species has two distinctly different regions: sapwood and heartwood. In addition to the major constituents, wood contains extraneous chemicals that can be removed by extraction with various solvents.