Survival to heat stress with and without heat-hardening in Drosophila melanogaster: interactions with larval density.

ARIAS L N; SAMBUCETTI P; SCANNAPIECO A C; LOESCHCKE V; NORRY F M

JOURNAL OF EXPERIMENTAL BIOLOGY

COMPANY OF BIOLOGISTS LTD

Lugar: Cambridge; Año: 2012 p. 2220 - 2225

0022-0949

Survival to a potentially lethal stress of high temperature is a genetically variable trait of thermal adaptation in many organisms. Living organisms cope with heat stress by basal or induced thermo-resistance. Here, we tested quantitative trait loci (QTL) for heat-stress survival in Drosophila melanogaster, with and without a cyclic heat hardening pre-treatment, for flies that were reared at both low (LD) and high (HD) density. Mapping populations were two panels of recombinant inbred lines (RIL) which were previously constructed from heat-stress-selected stocks: RIL-D48 and RIL-SH2, derived from backcrosses to the stock of low and high heat resistance, respectively. Heat-stress survival increased with heat hardening in both LD and HD flies. Besides, heat-stress survival increased consistently with density in non-hardened flies. There was a significant interaction between heat-hardening and density effects in RIL-D48. Several QTL were significant at both density and hardening treatments. Many QTL overlapped with thermotolerance-QTL identified for other traits in previous studies based on low density cultures only. However, three new QTL were found in HD only (cytological ranges: 12E-16F6; 30A3-34C2; 49C-50C). Previously found thermotolerance QTL were also significant for flies from HD cultures.