A1 Journal article (refereed)
Multiple paths to cold tolerance : the role of environmental cues, morphological traits and the circadian clock gene vrille (2021)


Poikela, N., Tyukmaeva, V., Hoikkala, A., & Kankare, M. (2021). Multiple paths to cold tolerance : the role of environmental cues, morphological traits and the circadian clock gene vrille. BMC Ecology and Evolution, 21, Article 117. https://doi.org/10.1186/s12862-021-01849-y


JYU authors or editors


Publication details

All authors or editors: Poikela, Noora; Tyukmaeva, Venera; Hoikkala, Anneli; Kankare, Maaria

Journal or series: BMC Ecology and Evolution

eISSN: 2730-7182

Publication year: 2021

Volume: 21

Article number: 117

Publisher: Biomed Central

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1186/s12862-021-01849-y

Research data link: https://doi.org/10.5061/dryad.98sf7m0fv

Publication open access: Openly available

Publication channel open access: Open Access channel


Abstract

Background
Tracing the association between insect cold tolerance and latitudinally and locally varying environmental conditions, as well as key morphological traits and molecular mechanisms, is essential for understanding the processes involved in adaptation. We explored these issues in two closely-related species, Drosophila montana and Drosophila flavomontana, originating from diverse climatic locations across several latitudes on the coastal and mountainous regions of North America. We also investigated the association between sequence variation in one of the key circadian clock genes, vrille, and cold tolerance in both species. Finally, we studied the impact of vrille on fly cold tolerance and cold acclimation ability by silencing it with RNA interference in D. montana.

Results
We performed a principal component analysis (PCA) on variables representing bioclimatic conditions on the study sites and used latitude as a proxy of photoperiod. PC1 separated the mountainous continental sites from the coastal ones based on temperature variability and precipitation, while PC2 arranged the sites based on summer and annual mean temperatures. Cold tolerance tests showed D. montana to be more cold-tolerant than D. flavomontana and chill coma resistance (CTmin) of this species showed an association with PC2. Chill coma recovery time (CCRT) of both species improved towards northern latitudes, and in D. flavomontana this trait was also associated with PC1. D. flavomontana flies were darkest in the coast and in the northern mountainous populations, but coloration showed no linkage with cold tolerance. Body size decreased towards cold environments in both species, but only within D. montana populations largest flies showed fastest recovery from cold. Finally, both the sequence analysis and RNAi study on vrille suggested this gene to play an essential role in D. montana cold resistance and acclimation, but not in recovery time.

Conclusions
Our study demonstrates the complexity of insect cold tolerance and emphasizes the need to trace its association with multiple environmental variables and morphological traits to identify potential agents of natural selection. It also shows that a circadian clock gene vrille is essential both for short- and long-term cold acclimation, potentially elucidating the connection between circadian clock system and cold tolerance.


Keywords: adaptation (change); natural selection; cold resistance; morphology (biology); environmental factors; circadian rhythm; genes; RNA interference; Drosophilidae

Free keywords: CTmin; CCRT; body colour; body weight; latitude; bioclimatic variables; RNA interference (RNAi); Drosophila montana; Drosophila flavomontana


Contributing organizations


Ministry reporting: Yes

Reporting Year: 2021

Preliminary JUFO rating: 2


Last updated on 2021-16-08 at 07:21