Physiological and Molecular Diversity in Radiation-resistant Fungi

The field of radio-resistant fungi is comparatively nascent, and there has been a lack of comprehensive information about the natural distribution of the ionising radiation-resistant fungi in natural environments. IRR fungi are predominantly isolated from regions that have been exposed to ionising radiation by anthropogenic activities. The radio-tolerant fungi have also been reported from several regions, as biofilms and as main contaminators. Additionally, the importance of melanin in IR resistance is emphasised by the greater abundance of melanised fungi in almost all types of habitats. Most of the radiation-resistant fungi are observed to accumulate melanin or some other pigments that are hypothesised to protect against radiation. It has also been proven and demonstrated that when the fungal spores are subjected to a collimated source of radiation, the germinated spores grow in the direction of the source of radiation, which is attributed to the presence of melanin. Radioprotection in melanised fungi is attributed to ionizing radiation-induced alteration in the redox potential of melanin. The identical resistance to ionising radiation in the case of WT as well as the pks1 mutant, deficient in the synthesis of melanin pigment.