Genome-wide examination of the natural solar radiation response in Shewanella oneidensis MR-1.
We previously reported that Shewanella oneidensis MR-1 is extremely sensitive to natural solar radiation (NSR). Here we analyzed the global transcriptional profile of MR-1 during a 1-h recovering period after exposure to ambient solar light at a dose that yields about 20% survival rate on a Luria-Bertani (LB) plate. We observed the induction of DNA damage-repair genes, the SOS response as well as detoxification strategies that we previously observed in MR-1 following artificial UV-A irradiation. Few prophage-related genes were induced by natural solar UV radiation, however, in contrast to what was observed following artificial UV-B irradiation. Overall, the cellular response to NSR in MR-1 was more similar to that of UV-A than that of UV-B, but additional genes involved in detoxification were induced compared with induction by either UV-B or UV-A or their sum. Thus, oxidative stress appeared to contribute greatly to the NSR-induced cytotoxic effects in MR-1. A total of 29.1% of genome showed differential expression following NSR exposure, which is much greater than following exposure by UV-B (4.0%), UV-A (8.2%) or their sum (10.7%). Our data suggest that NSR may impact biological processes in a much more complex manner than previously thought.
Qiu
Xiaoyun
X
Center for Microbial Ecology, Michigan State University, East Lansing 48824, USA.
Tiedje
James M
JM
Sundin
George W
GW
D015536:Down-Regulation; D015964:Gene Expression Regulation, Bacterial / Q000528:radiation effects*; D016678:Genome / Q000528:radiation effects*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020592:Shewanella / Q000235:genetics* / Q000528:radiation effects*; D014466:Ultraviolet Rays; D015854:Up-Regulation