Drought acclimation confers cold tolerance in the soil collembolan Folsomia candida

It has been noted that both summer drought and sub-zero winter temperatures induce the synthesis of sugars and polyols in invertebrate tissues. This h as led several authors to suggest that many of the adaptations, previously viewed as a response to cold, might be part of a more universal desiccation tolerance mechanism. Here we show that acclimation of the soil dwelling co llembolan Folsomia candida to a sublethal desiccation stress confers tolera nce to cold shock and a significant increase in the molar percent of membra ne fatty acids with a mid-chain double bond. These changes in membrane fatt y acids are interpreted as conferring a significant reduction in the transi tion temperature of cell membranes, as would be expected in acclimation to cold, and these changes are therefore interpreted as contributing to the cr oss-tolerance. Drought acclimation was also shown to trigger the synthesis of the 70 kDa family of heat-shock proteins (Hsp70). This group of heat sho ck proteins is implicated in the reestablishment of the normal three-dimens ional structure of partially unfolded proteins and therefore are also likel y to contribute to the observed cross-tolerance. This study provides eviden ce that the stresses exerted by desiccation and cold at the cellular level have sufficient similarities to induce overlapping adaptations. (C) 2001 El sevier Science Ltd. All rights reserved.