In vivo molecular analysis of tolerant ability in tardigrades

水熊虫在脱水后进入一种称为脱水的无代谢脱水状态，并在这种状态下耐受各种极端的环境压力。耐受能力的分子机制仍然未知，也没有进行体内分析。在此，我们首次分离出了脱水缓步动物色素缺陷突变体，并揭示了该突变体比野生型动物对辐射胁迫更敏感。大规模测序和与野生型基因组的比较揭示了多个突变基因。此外，我们对野生型缓步动物色素的性质进行了表征，这些色素可能是支持动物辐射耐受性的良好线索。

Tardigrades enter an ametabolic dehydrated state called anhydrobiosis upon desiccation and tolerate various extreme environmental stresses in such a state. The molecular mechanisms of the tolerant ability remain unknown and no in vivo analyses have been conducted. Here, we isolated pigment-deficient mutant of anhydrobiotic tardigrade for the first time and revealed that the mutant is more sensitive to radiation stress than wildtype animal. Massive sequencing and comparison with the wildtype genome revealed multiple mutated genes. Furthermore, we characterized the property of the pigments of wildtype tardigrades and these pigments could be good clues to support radiation tolerance in animals.