Florent, S. N. | Search bioRxiv

bioRxiv2023

Faecal glucocorticoid metabolite levels of intensive captive, free-range captive, and wild Tasmanian devils

Captivity can alter the stress physiology and behaviour of an animal in both the short- and long-term through repetitive exposure to novel stressors and, subsequently, may reduce the success of conservation efforts such as translocation and reintroduction. The Tasmanian devil (Sarcophilus harrisii) is threatened with extinction from a fatal facial tumour disease which has led to the establishment of an insurance meta-population designed for future reintroductions of disease-free devils. The meta-population is comprised of intensive captive and free-range captive environments; however, no study has yet examined the long-term physiological implications of captivity on devils. We used non-invasive faecal glucocorticoid metabolite (FGM) monitoring to determine if there were any differences in adrenal activity between intensive captive, free-range captive, and wild devils. FGMs were not age- or sexdependent, and we found that all population-types had similar intra-population variability and mean FGMs. In conclusion, both types of captive environment maintain stress profiles similar to wild devils.

zoology↗

bioRxiv2020

Oil body formation in Marchantia polymorpha is controlled by MpC1HDZ and serves as a defense against arthropod herbivores

The origin of a terrestrial flora in the Ordovician required adaptation to novel biotic and abiotic stressors. Oil bodies, a synapomorphy of liverworts, accumulate secondary metabolites, but their function and development are poorly understood. Oil bodies of Marchantia polymorpha develop within specialized cells as one single large organelle. Here, we show that a CLASS I HOMEODOMAIN LEUCINE-ZIPPER (C1HDZ) transcription factor controls the differentiation of oil body cells in two different ecotypes of the liverwort M. polymorpha, a model genetic system for early divergent land plants. In flowering plants, these transcription factors primarily modulate responses to abiotic stresss including drought. However, loss-of-function alleles of the single ortholog gene, MpC1HDZ, in M. polymorpha did not exhibit phenotypes associated with abiotic stress. Rather Mpc1hdz mutant plants were more susceptible to herbivory and total plant extracts of the mutant exhibited reduced antibacterial activity. Transcriptomic analysis of the mutant revealed a reduction in expression of genes related to secondary metabolism that was accompanied by a specific depletion of oil body terpenoid compounds. Through time lapse imaging we observed that MpC1HDZ expression maxima precede oil body formation indicating that MpC1HDZ mediates differentiation of oil body cells. Our results indicate that M. polymorpha oil bodies, and MpC1HDZ, are critical for defense against herbivory but not for abiotic stress-tolerance. Thus, C1HDZ genes were co-opted to regulate separate responses to biotic and abiotic stressors in two distinct land plant lineages.

plant biology↗