Meeting Abstract

P1.86  Tuesday, Jan. 4  Functional genomics of desiccation tolerance in cactophilic Drosophila mojavensis RAJPUROHIT, S.*; OLIVEIRA, C. C. ; ETGES, W. J. ; GIBBS , A. G. ; Uni. of Nevada, Las Vegas; Uni. of Arkansas, Fayetteville; Uni. of Arkansas, Fayetteville; Uni. of Nevada, Las Vegas subhash.rajpurohit@unlv.edu

Deserts and their inhabitants are particularly well-suited to an integrated molecule-to-ecosystem approach, because the extreme conditions of these habitats directly impact organism survival. We used whole transcriptome microarrays to assess gene expression in four natural populations of D. mojavensis from the Sonoran Desert. The recently sequenced genome of cactophilic D. mojavensis provides a unique opportunity to obtain an integrated understanding of resistance to arid conditions in desert animals. Over 500 genes differed in expression among populations, while over 855 were differentially expressed as a result of desiccation stress. Host cactus affected the expression of only 18 genes, and the magnitude of these differences was always less than 50%. However, interactions between host cactus, population, and desiccation affected nearly 1/3 of the transcriptome. Thus, host plants affected how different populations responded to desiccation. Functional annotation clustering resulted in 32 clusters, the majority of them involved in metabolism, olfaction, phototransduction, cuticle, and behavior. Overall, 296 differentially expressed genes were found to belong to a total of 20 KEGG pathways. Time series analysis of desiccation stress revealed up-regulation of genes involved in catabolism and transport, whereas the opposite was observed for genes involved in biosynthesis and locomotory activities. Overall we predict that coordinated expression of metabolism, behavior, and cuticle genes helps this fly to survive harsh desert conditions, and suggest that climate change will have varying effects on local populations feeding on different host plants.