Transcriptional Regulation of Metabolism Associated With the Increased Desiccation Resistance of the Cactophilic Drosophila mojavensis

Abstract

In Drosophila, adaptation to xeric environments presents many challenges, greatest among them the maintenance of water balance. Drosophila mojavensis, a cactophilic species from the deserts of North America, is one of the most desiccation resistant in the genus, surviving low humidity primarily by reducing its metabolic rate. Genetic control of reduced metabolic rate, however, has yet to be elucidated. We utilized the recently sequenced genome of D. mojavensis to create an oligonucleotide microarray to pursue the identities of the genes involved in metabolic regulation during desiccation. We observed large differences in gene expression between male and female D. mojavensis as well as both quantitative and qualitative sex differences in their ability to survive xeric conditions. As expected, genes associated with metabolic regulation and carbohydrate metabolism were differentially regulated between stress treatments. Most importantly, we identified four points in central metabolism (Glyceraldehyde 3-phosphate dehydrogenase, transaldolase, alcohol dehydrogenase, and phosphoenolpyruvate carboxykinase) that indicate the potential mechanisms controlling metabolic rate reduction associated with desiccation resistance. Furthermore, a large number of genes associated with vision pathways also were differentially expressed between stress treatments, especially in females, that may underlie the initial detection of stressful environments and trigger subsequent metabolic changes.

Repeated bouts of dehydration deplete nutrient reserves and reduce egg production in the mosquito Culex pipiens

“…In a recent study, we showed that heat shock protein 70 (Hsp70) and Hsp90 are essential in the mosquito's response to dehydration stress . Significant changes in metabolic genes have also been noted in response to dehydration resistance in Drosophila (Matzkin and Markow, 2009). In addition to changes in protein and gene levels, other molecules including trehalose and glycerol are likely to be generated to prevent protein interactions and reduce membrane changes as water levels within the mosquito fluctuate (Goyal et al, 2005;Watanabe, 2006).…”

Enhanced fertility and chill tolerance after cold-induced reproductive arrest in females of temperate species of the Drosophila buzzatii complex

“…Given that, in nature, tropical species face conditions that are above the thermal threshold that elicits cold reproductive arrest, the sharing of the reduction in metabolic rate across species may be a relictual plastic response that was present in the common ancestor of the buzzatii complex, despite the likely tropical origin of these flies. Alternatively, the reduction in metabolic rate may have been shaped by other stressors, such as desiccation, common to all cactophilic flies (Gibbs et al, 2003;Matzkin and Markow, 2009). A prediction of the latter interpretation is that similar responses are expected in other desert-adapted species.…”

Flavin-containing monooxygenases in aging and disease: Emerging roles for ancient enzymes

“…YUCCAs also promote drought resistance, and some FMOs are involved in osmoregulation in worms (85) and fish (88), in addition to producing the osmolyte TMAO in humans (43). Interestingly, there is overlap between the DR and osmotic stress pathways (89,90), and it is plausible that FMOs act at this intersection.…”