Fungicide‐induced melanin loss causes changes the transfer RNA modification pool in the radiation resistant fungi Cladosporium sphaerospermum

Abstract

Fungi have been found in extreme environments all over the world. Of particular interest, Cladosporium sphaerospermum is a filamentous fungus found to grow around the nuclear reactor at Chernobyl. Thus far, little is known of the mechanistic details that allow these fungi to survive such harsh oxidative conditions. The current hypothesis is that the pigment melanin contributes to growth through enhancing energy production mechanisms. In this work, we aim to identify the effect melanin presence on post‐transcriptional modifications to transfer RNA (tRNA) in C. sphaerospermum. Post‐transcriptional modifications affect translation of response proteins and may be indicative of an underlying mechanism. Prior to this study, the tRNA genes of C. sphaerospermum were unknown. Through a bioinformatics approach, 195 tRNA genes have been identified throughout the genome. The identification of tRNA genes gives information on anticodon preference as well as composition of the tRNA pool. Furthermore, treatment with the fungicides pyroquilon and tricyclazole induce varying levels of melanin loss. Dose‐response curves were generated for optimal dosing. Both fungicides cause phenotype changes, growth rate differences, and tRNA modification profiles alterations. Next, the impact of melanin loss on C. sphaerospermum survival in the presence of ionizing radiation (IR) was determined through growth rates post‐IR. The effect of exposure to ionizing radiation on tRNA modifications has been qualitatively and quantitatively determined using a liquid chromatography coupled with mass spectrometry system.Support or Funding InformationFunding support was provided by the Defense Threat Reduction Agency (DTRA) and the University of Cincinnati.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.