A proteomic analysis of Pseudevernia furfuracea after exposure to Cr+6 by MALDI-TOF mass spectrometry.

The problem of heavy metal pollution in nature has increased rapidly in recent years. Hexavalent chromium (Cr+6) is one of the most toxic heavy metals that cause environmental pollution. Although many studies in the literature that illuminate the stress response mechanisms of biological organisms such as bacteria, algae, and plants against heavy metals, there is limited information about revealing the protein level changes of lichen species in response to heavy metal stress. Here, we used a MALDI-TOF-based proteomic assay to determine protein level changes in Pseudevernia furfuracea after exposure to Cr+6 heavy metal stress at 6, 18 and 24 h. It was determined that expression levels of 26, 149 and 66 proteins changed in P. furfuracea. 6, 18 and 24 h after Cr+6 application compared to the control sample, respectively. We identified 9 common proteins expressed at three different time levels (6, 18, 24 h) and evaluated their protein-protein interaction profiles with the STRING tool. According to the results of the study, it was determined that the expression level of six proteins was up-regulated (OP4, KIP3, BNI5, VSP64, HSP 60, BCK1) and three proteins were down-regulated (MNS1, ABZ2, ATG4) from the expression level of nine proteins in total with Cr+6 exposure. It was determined that nine proteins were also found to be effective in biological processes such as stress signaling, transcription regulation and cellular detoxification metabolisms. To confirm the protein expression level, we analyzed the HSP60 protein by western blot assay. It has been shown that exposure to Cr+6 exposure in P. furfuracea caused an increase in HSP60 protein level compared to the control sample (non-exposed Cr+6). In this study, new knowledge are presented for the use of P. furfuracea as a biosorption agent in the removal of industrial wastes in biotechnological applications. © King Abdulaziz City for Science and Technology 2021.