Expression of a TardigradeDsupGene Enhances Genome Protection in Plants

DNA damage is one of the most impactful events in living organisms, leading to DNA sequence changes (mutation) and disruption of biological processes. A study has identified a protein called Damage Suppressor Protein (Dsup) in the tardigradeRamazzotius varieornatusthat has shown to reduce the effects of radiation damage in human cell cultures (Hashimoto in Nature Communications 7:12808, 2016). We have generated tobacco plants that express the codon-optimized tardigradeDsupgene and examined their responses when treated with mutagenic chemicals, ultraviolet (UV) and ionizing radiations. Our studies showed that compared to the control plants, theDsup-expressing plants grew better in the medium containing mutagenic ethylmethane sulfonate (EMS). RT-qPCR detected distinct expression patterns of endogenous genes involved in DNA damage response and repair in theDsupplants in response to EMS, bleomycin, UV-C and X-ray radiations. Comet assays revealed that the nuclei from theDsupplants appeared more protected from UV and X-ray damages than the control plants. Overall, our studies demonstrated thatDsupgene expression enhanced tolerance of plants to genomutagenic stress. We suggest the feasibility of exploring genetic resources from extremotolerant species such as tardigrades to impart plants with tolerance to stressful environments for future climate changes and human space endeavors.