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 tardigrade Ramazzotius varieornatus that 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 tardigrade Dsup gene and examined their responses when treated with mutagenic chemicals, ultraviolet (UV) and ionizing radiations. Our studies showed that compared to the control plants, the Dsup-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 the Dsup plants in response to EMS, bleomycin, UV-C and X-ray radiations. Comet assays revealed that the nuclei from the Dsup plants appeared more protected from UV and X-ray damages than the control plants. Overall, our studies demonstrated that Dsup gene 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.

DNA 损伤是生物体中最具影响力的事件之一，导致 DNA 序列变化（突变）和生物过程的破坏。一项研究在缓步动物Ramazzotius varieornatus中发现了一种名为损伤抑制蛋白 (Dsup) 的蛋白质，该蛋白质已被证明可以减少人类细胞培养物中辐射损伤的影响（Hashimoto in Nature Communications 7:12808, 2016）。我们培育了表达密码子优化的缓步动物Dsup基因的烟草植物，并检查了它们在用诱变化学品、紫外线 (UV) 和电离辐射处理时的反应。我们的研究表明，与对照植物相比，表达Dsup的植物在含有诱变甲磺酸乙酯(EMS)的培养基中生长得更好。 RT-qPCR 检测到Dsup植物中参与 EMS、博莱霉素、UV-C 和 X 射线辐射的 DNA 损伤反应和修复的内源基因的不同表达模式。彗星试验显示， Dsup植物的细胞核似乎比对照植物更能免受紫外线和 X 射线的损害。总体而言，我们的研究表明Dsup基因表达增强了植物对基因突变胁迫的耐受性。我们建议探索来自缓步动物等极端耐受物种的遗传资源的可行性，以赋予植物对未来气候变化和人类太空努力的压力环境的耐受性。