Biology subjects

Anfora, G.

Publications and source records attributed to Anfora, G..

3 recordsLinked to original sources

bioRxiv2022

Basal and stress-induced expression changes consistent with water loss reduction explain desiccation tolerance of natural Drosophila melanogaster populations

BackgroundClimate change is one of the main factors shaping the distribution and biodiversity of organisms, among others by greatly altering water availability, thus exposing species and ecosystems to harsh desiccation conditions. Insects are especially threatened by these challenging dry environments, because of their small size and thus large surface area to volume ratio. Integrating transcriptomics and physiology is key to advancing our knowledge on how species cope with desiccation stress, and these studies are still best accomplished in model organisms. ResultsHere, we characterized the natural variation of European D. melanogaster populations across climate zones and found that strains from arid regions were similar or more tolerant to desiccation compared with strains from temperate regions. Tolerant and sensitive strains differed not only in their transcriptomic response to stress but also in their basal expression levels. We further showed that gene expression changes in tolerant strains correlated with their physiological response to desiccation stress and with their cuticular hydrocarbon composition. Transposable elements, which are known to influence stress response across organisms, were not found to be enriched nearby differentially expressed genes. Finally, we identified several tRNA-derived small RNA fragments that differentially targeted genes in response to desiccation stress. ConclusionsOur results showed that by integrating transcriptomics with physiological trait analysis we can pinpoint the genetic basis of the differences in tolerance to desiccation stress found in natural D. melanogaster populations. Moreover, we showed that, beyond starvation and aging, tRNA-derived small RNA fragments (tRFs) appear to be relevant post-transcriptional gene regulators in response to desiccation stress.

evolutionary biology↗

bioRxiv2019

Exploring multiple sensory systems in ovipositors of Drosophila suzukii and related species with different egg-laying behaviour

Drosophila suzukii is an invasive agricultural pest species that lays eggs in fruit during ripening, while most closely related Drosophila species use rotten matter as oviposition substrates. This behaviour is allowed by an enlarged and serrated ovipositor that can pierce intact fruit skin. D. suzukii combines multiple sensory systems (mechanosensation, olfaction, and taste) to select oviposition sites. Here, we test the hypothesis that the D. suzukii ovipositor is involved in these sensory modalities. We first investigate the ovipositor gene expression using a comparative framework of four Drosophila species with gradual changes in ovipositor morphology to identify evolutionary adaptations specific to D. suzukii. Results show transcription of chemoreceptors and mechanoreceptors in the four species, with a common core of sensory receptors expressed in all of them. Then, we demonstrate that sensory structures present in the distal tip of the D. suzukii ovipositor are mechanosensory-like sensilla, and that the degenerin/epithelial sodium channel ppk is expressed in homologous structures in Drosophila melanogaster. Our results suggest the D. suzukii ovipositor playing a role in mechanosensation, which might be shared with other Drosophila species.

zoology↗

bioRxiv2017

Genome Comparisons Indicate Recent Transfer Of wRi-Like Wolbachia Between Sister Species Drosophila suzukii And D. subpulchrella

Wolbachia endosymbionts may be acquired by horizontal transfer, by introgression through hybridization between closely related species, or by cladogenic retention during speciation. All three modes of acquisition have been demonstrated, but their relative frequency is largely unknown. Drosophila suzukii and its sister species D. subpulchrella harbor Wolbachia, denoted wSuz and wSpc, very closely related to wRi, identified in California populations of D. simulans. However, these variants differ in their induced phenotypes: wRi causes significant cytoplasmic incompatibility (CI) in D. simulans, but CI has not been detected in D. suzukii or D. subpulchrella. Our draft genomes of wSuz and wSpc contain full-length copies of 703 of the 734 single-copy genes found in wRi. Over these coding sequences, wSuz and wSpc differ by only 0.004% (i.e., 28 of 704,883 bp); they are sisters relative to wRi, from which each differs by 0.014-0.015%. Using published data from D. melanogaster, Nasonia wasps and Nomada bees to calibrate relative rates of Wolbachia versus host nuclear divergence, we conclude that wSuz and wSpc are too similar - by at least a factor of 100 - to be plausible candidates for cladogenic transmission. These three wRi-like Wolbachia, which differ in CI phenotype in their native hosts, have different numbers of orthologs of genes postulated to contribute to CI; and the CI loci differ at several nucleotides that may account for the CI difference. We discuss the general problem of distinguishing alternative modes of Wolbachia acquisition, focusing on the difficulties posed by limited knowledge of variation in absolute and relative rates of molecular evolution for host nuclear genomes, mitochondria and Wolbachia.

evolutionary biology↗