Ice nucleation inducers have been widely used in ski resorts all over the world to create artificial snow and sustain the practice of snow sports, to deal with the constant drop in natural snow precipitation given global warming. Some resorts based in Kosciuszko National Park use a commercial product called Snomax, with ice nucleation activity reportedly derived from a protein purified from the fermentation of the Pseudomonas syringae bacterium. Some strains of this bacterium carry numerous toxin and antimicrobial resistance genes, which can cause severe damage to plants. This project aims to accurately investigate the composition of this ice nucleation agent, and assess any potential impacts it may have on Alpine vegetation.
The amino acid compositional analysis of Snomax showed that it is approximately 50% protein, and further analysis of chemical composition is underway to determine the other components. A proteomic characterization using SDS-PAGE and nanoflow liquid chromatography–tandem mass spectrometry identified >2000 proteins, all of them related to P. syringae bacterium. Bacterial DNA sequencing will be performed to identify accurately the strains existing in this product.
To assess potential environmental impacts, molecular analysis of field collected leaves and soil has been carried out. Collection of five different endemic Alpine plant species and soil was performed after the end of the 2022 and 2023 ski seasons, at three different altitudes within the Thredbo ski area, and in three geographically similar sides at matching altitudes, west of the resort in the Dead Horse Gap area. While the sites within the resort were exposed to the use of Snomax, the sites outside the resort were not. Soil samples were collected from each site, along with leaves from Eucalyptus niphophila, Nematolepis ovatifolia, Tasmannia xerophila, Ozothamnus secundiflorus, and Olearia phlogopappa. Protein extraction was optimised and an initial proteomic characterization of N. ovatifolia from sites 1 and 6 using FASP digestion and nanoflow liquid chromatography–tandem mass spectrometry identified >1000 proteins. The proteomic characterization of other species and the analysis of proteome expression of plants exposed to Snomax are currently in progress. Concurrent bacterial DNA sequencing of the leaf phyllosphere is also in progress, and preliminary results revealed the predominant bacterial species identified were Crinalium epipsammum, Variovorax, and Acidovorax sp. strain KKS102.