Adaptation to seasonality and the winter freeze

Abstract

Flowering plants initially diversified during the Mesozoic era at least 140 million years ago in regions of the world where temperate seasonal environments were not encountered. Since then several cooling events resulted in the contraction of warm and wet environments and the establishment of novel temperate zones in both hemispheres. In response, less than half of modern angiosperm families have members that evolved specific adaptations to cold seasonal climates, including cold acclimation, freezing tolerance, endodormancy, and vernalization responsiveness. Despite compelling evidence for multiple independent origins, the level of genetic constraint on the evolution of adaptations to seasonal cold is not well understood. However, the recent increase in molecular genetic studies examining the response of model and crop species to seasonal cold offers new insight into the evolutionary lability of these traits. This insight has major implications for our understanding of complex trait evolution, and the potential role of local adaptation in response to past and future climate change. In this review, we discuss the biochemical, morphological, and developmental basis of adaptations to seasonal cold, and synthesize recent literature on the genetic basis of these traits in a phylogenomic context. We find evidence for multiple genetic links between distinct physiological responses to cold, possibly reinforcing the coordinated expression of these traits. Furthermore, repeated recruitment of the same or similar ancestral pathways suggests that land plants might be somewhat pre-adapted to dealing with temperature stress, perhaps making inducible cold traits relatively easy to evolve.

Evolution of VRN2/Ghd7-Like Genes in Vernalization-Mediated Repression of Grass Flowering

“…The attainment of flowering competence in response to vernalization has evolved multiple times independently across major lineages of angiosperms and is hypothesized to be a key adaptation facilitating niche shifts from the tropics to the temperate zone (Ream et al, 2012;Preston and Sandve, 2013). One such niche transition occurred in the grass subfamily Pooideae, members of which are distributed primarily in the northern temperate zone (Hartley, 1973;Edwards and Smith, 2009) and are heavily relied upon for grain, turf, and fodder.…”

“…It is hypothesized that vernalization responsiveness evolved early during the diversification of Pooideae, as a key adaptation allowing for their transition into the temperate zone (Preston and Sandve, 2013;Fjellheim et al, 2014). Within core Pooideae, many species have been characterized as vernalization responsive (Heide, 1994;Grass Phylogeny Working Group, 2001;Grass Phylogeny Working Group II, 2012).…”

Disturbance and distributions: avoiding exclusion in a warming world

“…For example, frost tolerance determines the upper-elevation limit of numerous plant species (Ohsawa 1995, Ricklefs 2005, Preston and Sandve 2013. Climatic limits can also be inferred from the inability of species to maintain positive population growth above their high-elevation limits even in the absence of competitors (e.g., HilleRisLambers et al 2013).…”

Optimal Regulation of the Balance between Productivity and Overwintering of Perennial Grasses in a Warmer Climate

“…In regions with a long winter, a storage of organic reserves, particularly carbohydrates, are necessary for maintenance respiration, stress responses, and early spring regrowth. In addition, carbohydrates have specific roles as osmolytes and protectants of cellular components [13,40], and winter survival ability is often associated with a higher concentration of both simple sugars and fructans in the basal parts of the shoot attained during cold acclimation [64][65][66][67]. As described above, winter cereals maintain CO 2 -fixation rates at low temperatures due to photosynthetic acclimation, a mechanism, which combined with restrictions on leaf growth, ensures that a storage of carbohydrates is accumulating.…”

“…The annual recurrent periods of winter stresses or summer droughts in some regions have led to the evolution of seasonal acclimation and de-acclimation processes regulating the level of resistance to seasonal stresses [11][12][13]. These processes, which are largely regulated by temperature and photoperiod, correlate with changes in growth, development, and dormancy status [13][14][15], and latitudinal clines in growth responses to temperature and photoperiod have been described [16]. Acclimation and de-acclimation are associated with cessation and resumption of leaf growth, respectively, suggesting a classical growth-stress survival trade-off [17] in the adaptation to seasonal stresses [15].…”