Rapid diagnosis of biological colonization in cultural artefacts using the MinION nanopore sequencing technology

Living organisms leave traces of DNA in the objects they colonize and contribute to the microbiome of a given environment. The microbiome of cultural objects is an indicator of their conservation status and restoration history. Two oil paintings on canvas from the 18th and 19th centuries, one of them (painting M) showing an active fungal colonization, while the second (painting N) with a cracked varnish surface, were investigated by metagenomic analyses using whole genome amplification (WGA) and the Nanoporore sequencing technology. The main objective was to evaluate the advantages of this cutting-edge strategy for the diagnosis of microbial contaminants in cultural artefacts and to establish a fast and simple molecular protocol for end users. WGA metagenomics showed to be successful for a rapid diagnosis, showing a higher amount of eukaryotes in painting M compared to painting N, correlated with the high amount of fungi on its surface. The microbiomes of both paintings revealed interesting differences according to their different conservation status, but also intriguing similarities between a cracked and a mouldy surface. Fungi, belonging to the genus Aspergillus and bacteria of the order Burkholderiales, proved to be the key factors in the biodeterioration of the damaged painting.