Plant Nutrition Laboratory, Faculty of Natural Sciences III, Institute of Agricultural and Nutritional Sciences (IAEW), Martin Luther University of Halle-Wittenberg, Halle (Saale), Germany; Agrochemisches Institut Piesteritz e.V., Lutherstadt Wittenberg, Germany.
Plant Biol (Stuttg). 2014 Nov;16(6):1058-64. doi: 10.1111/plb.12167. Epub 2014 Feb 17.
The deterioration of seeds during prolonged storage results in a reduction of viability and germination rate. DNA damage is one of the major cellular defects associated with seed deterioration. It is provoked by the formation of reactive oxygen species (ROS) even in the quiescent state of the desiccated seed. In contrast to other stages of seed life, DNA repair during storage is hindered through the low seed water content; thereby DNA lesions can accumulate. To allow subsequent seedling development, DNA repair has thus to be initiated immediately upon imbibition. Poly(ADP-ribose) polymerases (PARPs) are important components in the DNA damage response in humans. Arabidopsis thaliana contains three homologues to the human HsPARP1 protein. Of these three, only AtPARP3 was very highly expressed in seeds. Histochemical GUS staining of embryos and endosperm layers revealed strong promoter activity of AtPARP3 during all steps of germination. This coincided with high ROS activity and indicated a role of the nuclear-localised AtPARP3 in DNA repair during germination. Accordingly, stored parp3-1 mutant seeds lacking AtPARP3 expression displayed a delay in germination as compared to Col-0 wild-type seeds. A controlled deterioration test showed that the mutant seeds were hypersensitive to unfavourable storage conditions. The results demonstrate that AtPARP3 is an important component of seed storability and viability.
种子在长时间储存过程中的劣化会导致活力和发芽率降低。DNA 损伤是与种子劣化相关的主要细胞缺陷之一。即使在干燥种子的静止状态下，活性氧 (ROS) 的形成也会引发这种损伤。与种子生命的其他阶段不同，由于种子含水量低，储存过程中的 DNA 修复受到阻碍；因此，DNA 损伤可能会积累。为了允许随后的幼苗发育，因此必须在吸胀时立即启动 DNA 修复。聚（ADP-核糖）聚合酶（PARPs）是人类 DNA 损伤反应中的重要组成部分。拟南芥含有三种与人 HsPARP1 蛋白同源的蛋白。在这三种蛋白中，只有 AtPARP3 在种子中高度表达。胚胎和胚乳层的组织化学 GUS 染色显示，在萌发的所有阶段，AtPARP3 的启动子活性都很强。这与高 ROS 活性一致，并表明核定位的 AtPARP3 在萌发过程中的 DNA 修复中发挥作用。因此，与 Col-0 野生型种子相比，缺乏 AtPARP3 表达的储存 parp3-1 突变体种子的萌发延迟。受控劣化试验表明，突变体种子对不利的储存条件更为敏感。结果表明，AtPARP3 是种子贮藏能力和活力的重要组成部分。
