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

Abstract

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. As expected, genes related to cold hardiness and defense were over-represented. Carbohydrate biosynthesis and transport-related genes were also actively expressed in winter/dormancy stems. Further biochemical analyses verified the dormancy/winter transcription phenotype. More than 60% of the winter upregulated transcription factors (TFs) were related to either biotic or abiotic stress. This finding substantiates that the major transcriptional network of winter/dormancy stems is related to stress tolerance, such as dehydration, cold tolerance and defense. Furthermore, during winter/dormancy, preferential expression of genes involved in cell wall biosynthesis or modification, indirect transcriptional regulation (RNA metabolism) and chromatin modification/remodeling were observed. Taken together, these findings show that regulation of gene expression associated with winter survival and maintenance extends beyond control by promoter-binding TFs to include regulation at the post-transcriptional and chromatin levels.

Tracing a key player in the regulation of plant architecture: the columnar growth habit of apple trees (Malus × domestica)

“…Aintegumenta-like genes (regulators of cell division) and dormancy-induced MADS-box genes are downstream targets of CO/FT (Karlberg et al 2011;Yamane et al 2011). Additional downstream effects related to dormancy induction are the upregulation of genes associated with cold hardiness and drought, defense, carbohydrate synthesis and transport, cell wall biosynthesis or modification as well as RNA metabolism and chromatin modification/remodeling (Ruttink et al 2007;Park et al 2008;Ko et al 2011). In contrast, the transition from dormancy to active growth is characterized by the induction of flowering pathways, RNA metabolism and protein biosynthesis and transport (Larisch et al 2012).…”

Custom Microarray Analysis for Transcript Profiling of Dormant Vegetative Buds of Japanese Apricot during Prolonged Chilling Exposure

“…(Derory et al, 2006), poplar (Populus spp.) (Ko et al, 2011;Ruttink et al, 2007), raspberry (Rubus idaeus L.) (Mazzitelli et al, 2007), grapevine (Vitis riparia Michx.) (Mathiason et al, 2009), blackcurrant (Ribes nigrum L.) (Hedley et al, 2010), and leafy spurge (Euphobia esula L.) (Doğramaci et al, 2010).…”

Poplar Wood Rays Are Involved in Seasonal Remodeling of Tree Physiology

“…Previous studies on seasonality have focused on hormonal and structural aspects of cambium reactivation, cambial activity, and cessation (Lachaud, 1989;Catesson, 1994;Savidge, 1996;Uggla et al, 1996;Baba et al, 2011), bud set (Rohde et al, 2011b), and frost hardening (Ko et al, 2011). However, the molecular basis of such seasonal behavior, the related signaling system, and the repercussions on nutrient cycles in trees remain largely unknown.…”

“…It thus comes as no surprise that, when comparing the "summer and winter gene expression" of trees, thousands of transcripts appear differentially regulated (Ko et al, 2011).…”