NGS applications to understand invertebrate biodiversity of Antarctica and mechanisms of gene expression involved in climatic changes

• Main Author: Claudio Cucini
• Other Authors: Cucini, Claudio, CARAPELLI, ANTONIO
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Università degli Studi di Siena 2022
• Subjects: Settore BIO/05 - Zoologia; Antarctic; Victoria Land; Antarc*; Antarctic Springtail; Antarctica; Springtail
• Online Access: http://hdl.handle.net/11365/1214717; https://doi.org/10.25434/claudio-cucini_phd2022

Human activities, such as greenhouse emissions and pollution, are leading to global warming, environmental changes and biodiversity reduction. Pristine environments such as those of Antarctica are not immune to these phenomena, as is noticeable from the temperature shifts and ice-melting registered within the continent in recent decades. To date, many scientists focused on how marine species react to these changes but no molecular data are currently available for continental terrestrial invertebrates and in particular for Collembola (=springtails). Therefore, part of my PhD project was to study the transcriptomic response of the endemic Antarctic springtail Cryptopygus terranovus following a mid-term exposure of 20 days at 18°C. Expression data were compared with wild specimens sampled in native environment. Although individual plasticity in transcript modulation was recorded, several pathways appear to be differentially modulated: protein catabolism, fatty acid metabolism and a sexual response characterized by spermatid development were induced, while lipid catabolism was downregulated in treated samples. Moreover, the temperature experienced by these micro-invertebrates is a pivotal parameter to understand these animals' ecology and physiology. However, at present, detailed knowledge of microhabitat physical conditions in Antarctica is limited and biased towards sub-Antarctic and maritime Antarctic regions. To better understand these temperature conditions, it was analysed a year-round temperature data in ponds and soils in an area of the Victoria Land coast, comparing these measurements with air temperatures from the closest automatic weather station. Important difference in temperature dynamics between the air, soil and pond datasets was registered. Ponds were the warmest sites overall, mostly differing with the air temperatures due to their greater thermal capacity, which also influenced their patterns of freeze-thaw cycles and mean daily thermal excursion. Furthermore, to better understand the biodiversity ...