Temperature‐induced gene expression associated with different thermal reaction norms for growth rate

Abstract

Although nearly all organisms are subject to fluctuating temperature regimes in their natural habitat, little is known about the genetics underlying the response to thermal conditions, and even less about the genetic differences that cause individual variation in thermal response. Here, we aim to elucidate possible pathways involved in temperature-induced phenotypic plasticity of growth rate. Our model organism is the collembolan Orchesella cincta that occurs in a wide variety of habitats and is known to be adapted to local thermal conditions. Because sequence information is lacking in O. cincta, we constructed cDNA libraries enriched for temperature-responsive genes using suppression subtractive hybridization. We compared gene expression of O. cincta with steep thermal reaction norms (high plasticity) to those with flat thermal reaction norms (low plasticity) for juvenile growth after exposure to a temperature switch composed of a cooling or a warming treatment. Using suppression subtractive hybridization, we found differential expression of ten nuclear genes, including several genes involved in energy metabolism, such as pantothenate kinase and carbonic anhydrase. In addition, seven mitochondrial genes were found in the cloned subtracted library, but further analysis showed this was caused by allelic variation in mitochondrial genes in our founder population, and that a specific haplotype was associated with high thermal responsiveness. Future work will focus on candidate genes from pathways such as the oxidative phosphorylation and biosynthesis of coenzyme A which are possibly involved in thermal responsiveness of juvenile growth rate.

Latitudinal patterns of phenology and age‐specific thermal performance across six Coenagrion damselfly species

“…It, however, also suggests that whether strong acclimation responses will evolve likely depend on several factors that affect the costs and benefits of acclimation. Acclimation involves a great number of energetically costly physiological changes (Hoffmann 1995, Huey and Berrigan 1996, Ellers et al 2008, and very rapid acclimation is presumably much more costly (or even impossible) than slow acclimation (Kelty and Lee 1999). In addition, how much more an individual will be able to grow by acclimating will depend both on how much it can increase in growth performance at a given temperature and on how much time is spent at that temperature (Kingsolver et al 2001).…”

The significance of genome-wide transcriptional regulation in the evolution of stress tolerance

“…This mechanism is not inconsistent with the finding of a common expression footprint of 252 up-regulated genes in seven tissues of cold-acclimated common carp, Cyprinus carpio (Gracey et al 2004). It would be intriguing to know whether an analogous mechanism underpins the specific suite of temperature-induced transcriptional changes, involving a number of energy metabolism genes observed in the soil-dwelling invertebrate O. cincta (Ellers et al 2008). The HMGB1 response warrants further studies to ascertain its ubiquity as a modulator of acclimation to cold stress across a range of vertebrate and invertebrate taxa, and also to determine whether or not it facilitates transcriptomic adjustments in response to non-thermal stressors.…”

Maximized PUFA measurements improve insight in changes in fatty acid composition in response to temperature

“…O. cincta is a surface-dwelling soil arthropod that occurs in a wide variety of seasonal habitats. It is adapted to local conditions including temperature (Timmermans et al, 2005;Bahrndorff et al, 2007;Liefting and Ellers, 2008), and shows significant variation in thermal responsiveness of juvenile growth rate (Driessen et al, 2007;Ellers et al, 2008). We acclimatized female O. cincta to two temperatures, 51C and 251C.…”