Molecular signatures of environmental adaptation mechanisms of Rhizocarpon geographicum in Horseshoe Island (west of the Antarctic Peninsula) and Türkiye

The adaptation of lichen species to different habitats and extreme conditions is due to rapid changes in expressions of the genes in their genetic backgrounds. In this study, lichen samples were collected from two different regions: from Horseshoe Island, located to the west of the Antarctic Peninsula and from the west coast of Turkiye. The nrITS gene regions of the samples were studied and the phylogenetic positions of the samples were confirmed as Rhizocarpon geographicum (L.) DC. After DNA barcoding of R. geographicum, expression differences of three below-specified stress genes were revealed. Comparative determinations of the changes in the expressions of the multiprotein binding factor-1 (MBF-1), polyketide synthase (PKS), and photosystem II D1 protein (psbA) genes due to temperature or other environmental stress change stress were performed by a real-time PCR. Specifically, under cold stress conditions such as those found on Horseshoe Island, the MBF-1 gene was highly expressed, while PKS and psbA gene expression levels were lower compared to the west coast of Turkiye. The results of this study, which is the first in its field, highlight the adaptation of Rhizocarpon geographicum specimens to those habitats and regional climate. Specimen collected from different geographical regions exhibited gene expression differences.