Oak stands along an elevation gradient have different molecular strategies for regulating bud phenology

Abstract

Background Global warming raises serious concerns about the persistence of species and populations locally adapted to their environment, simply because of the shift it produces in their adaptive landscape. For instance, the phenological cycle of tree species may be strongly affected by higher winter temperatures and late frost in spring. Given the variety of ecosystem services they provide, the question of forest tree adaptation has received increasing attention in the scientific community and catalyzed research efforts in ecology, evolutionary biology and functional genomics to study their adaptive capacity to respond to such perturbations. Results In the present study, we used an elevation gradient in the Pyrenees Mountains to explore the gene expression network underlying dormancy regulation in natural populations of sessile oak stands sampled along an elevation cline and potentially adapted to different climatic conditions mainly driven by temperature. By performing analyses of gene expression in terminal buds we identified genes displaying significant dormancy, elevation or dormancy-by-elevation interaction effects. Our Results highlighted that low- and high-altitude populations have evolved different molecular strategies for minimizing late frost damage and maximizing the growth period, thereby increasing potentially their respective fitness in these contrasting environmental conditions. More particularly, population from high elevation overexpressed genes involved in the inhibition of cell elongation and delaying flowering time while genes involved in cell division and flowering, enabling buds to flush earlier were identified in population from low elevation. Conclusion Our study made it possible to identify key dormancy-by-elevation responsive genes revealing that the stands analyzed in this study have evolved distinct molecular strategies to adapt their bud phenology in response to temperature.

Leaf gene expression trajectories during the growing season are consistent between sites and years in American beech

“…These works have largely focused on a single site and/or a single growing season. However, a study on oak represents a rare exception spanning a decade in a multiple site setting [33]. Here, we have produced a detailed study of leaf gene expression in Fagus grandifolia in two distinct populations in the eastern United States through the growing season in multiple years.…”

“…Functional responses to these climatic changes, however, are complex and difficult to demonstrate against the background noise of ecological variation. Because genes fundamentally drive all these mechanisms, transcriptomics might offer a tool towards identifying patterns and to advance our understanding of the mechanisms of response to climate change [29][30][31][32][33].…”

Effect of temperature on circadian clock functioning of trees in the context of global warming

“…Furthermore, this study focusses on the effect of temperature on just one aspect of forest dynamics – namely, seedling growth. Other aspects of forest dynamics have recently been assessed for their thermal susceptibility, such as spring phenology (3, 4, 50) and leaf senescence (51) of adult trees. Interestingly, both of these traits proved to be controlled, at least in part, by the oscillator (52, 53).…”

Leaf gene expression trajectories during the growing season are consistent between sites and years in American beech

“…There have been a few transcriptomic time course studies produced to understand multi-year, multi-season dynamics in plants [19, 34, 35, 44, 45]). These works have largely focused on a single site and/or a single growing season with a single study on oak representing a rare exception spanning a decade in a multiple site setting [33]. Here, we have produced a detailed study of leaf gene expression in Fagus grandifolia in two distinct populations in the eastern United States through the growing season in multiple years.…”

“…Functional responses to these climatic changes, however, are complex and difficult to demonstrate against the background noise of ecological variation. Because genes fundamentally drive all these mechanisms, gene expression might offer a tool towards identifying patterns to advance our understanding of the mechanisms of organismal response to climate change through phenology [29][30][31][32][33].…”