Accelerating chill coma recovery time in a cold susceptible Drosophila by introgression and selection

MENSCH, J; SCHILMAN, PE; SIMON, H; HASSON, E; HURTADO, J

Tartu

Conferencia; International Symposium on the Environmental Physiology of Ectotherms and Plants; 2017

Environmental temperature is considered one of themost important abiotic factors influencing the geographic distributions of thespecies. In particular, the genus Drosophila represents a vast collection oforganisms adapted to a wide variety of environmental temperatures resulting inmarked interspecific thermal tolerance differences. In this study, we focus on twoSouth American species of the Drosophila buzzatii complex, D. borborema and D.koepferae, a chill susceptible and a cold tolerant species, respectively. Giventhat these species have the capacity to be crossed in the lab andproduce fertile hybrids, we aimed to enhance chill coma recovery time in the coldsusceptible species by introgression of genomic regions from the cold tolerantspecies followed by several generations of artificial selection. After 10generations of artificial selection and back-cross at 25°C, some introgressionlines reached a similar chill coma recovery time as the cold tolerant Drosophila. Based on these results, wetested whether introgression and selection for rapid chill coma recovery timeaffected the low critical temperature (CTmin), another popular andwell-describe metric of cold tolerance. Interestingly, introgression linesmaintained CTmin values of the chill susceptible species. Finally, weinvestigated how cold acclimation affect chill coma recovery time and CTmin. Coldacclimation improved cold tolerance of introgression lines, by lowering CTminand accelerating chill coma recovery time. However, cold acclimated introgressionlines showed similar CTmin and chill coma recovery time as cold acclimated chillsusceptible species, hidden the differences found by selection under rearingconditions (25°C). Taken together, our results indicate that mechanisms thatset the time to recovery from chill coma seems to be independent of the onesthat control the low critical temperature and cold acclimation.