PDF(Pubmed)
Abstract：
Mitochondria and plastids, originated as ancestral endosymbiotic bacteria, contain their own DNA sequences. These organelle DNAs (orgDNAs) are, despite the limited genetic information they contain, an indispensable part of the genetic systems but exist as multiple copies, making up a substantial amount of total cellular DNA. Given this abundance, orgDNA is known to undergo tissue-specific degradation in plants. Previous studies have shown that the exonuclease DPD1, conserved among seed plants, degrades orgDNAs during pollen maturation and leaf senescence in Arabidopsis. However, tissue-specific orgDNA degradation was shown to differ among species. To extend our knowledge, we characterized DPD1 in rice in this study. We created a genome-edited (GE) mutant in which OsDPD1 and OsDPD1-like were inactivated. Characterization of this GE plant demonstrated that DPD1 was involved in pollen orgDNA degradation, whereas it had no significant effect on orgDNA degradation during leaf senescence. Comparison of transcriptomes from wild-type and GE plants with different phosphate supply levels indicated that orgDNA had little impact on the phosphate starvation response, but instead had a global impact in plant growth. In fact, the GE plant showed lower fitness with reduced grain filling rate and grain weight in natural light conditions. Taken together, the presented data reinforce the important physiological roles of orgDNA degradation mediated by DPD1.
摘要：
线粒体和质体，起源于祖先的内共生细菌，包含自己的DNA序列。这些细胞器DNA（orgDNA）是，尽管它们包含的遗传信息有限，遗传系统中不可或缺的一部分，但作为多个副本存在，构成了细胞总DNA的大量。鉴于这种丰富，已知orgDNA在植物中经历组织特异性降解。以前的研究表明，外切核酸酶DPD1在种子植物中保守，拟南芥在花粉成熟和叶片衰老过程中降解orgDNA。然而,组织特异性orgDNA降解在物种之间显示不同。为了扩展我们的知识，在这项研究中，我们对水稻中的DPD1进行了表征。我们创建了基因组编辑（GE）突变体，其中OsDPD1和OsDPD1样被灭活。该GE植物的表征表明DPD1参与花粉orgDNA降解，而对叶片衰老过程中orgDNA降解没有显着影响。来自不同磷酸盐供应水平的野生型和GE植物的转录组的比较表明，orgDNA对磷酸盐饥饿反应影响很小，而是对植物生长产生了全球影响。事实上,在自然光条件下，GE植物表现出较低的适应性，籽粒灌浆率和粒重降低。一起来看,所提供的数据加强了DPD1介导的orgDNA降解的重要生理作用。
