Fujian Provincial Key Laboratory of Plant Functional Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Plant Physiol. 2020 Nov;184(3):1348-1362. doi: 10.1104/pp.20.00832. Epub 2020 Sep 8.
Coordination of gene expression in mitochondria, plastids, and nucleus is critical for plant development and survival. Although WHIRLY2 (WHY2) is involved in mitochondrial genome repair and affects the DNA copy number of the mitochondrial genome, the detailed mechanism of action of the WHY2 protein is still elusive. In this study, we found that WHY2 was triple-localized among the mitochondria, plastids, and the nucleus during Arabidopsis () aging. Overexpressing WHY2 increased starch granule numbers in chloroplasts of pericarp cells, showing a partially dry, yellowing silique and early senescence leaves. Accordingly, WHY2 protein could directly activate the expression of and () gene expression and repress gene expression in the nucleus, leading to alteration of starch accumulation and transport in pericarp cells. In contrast, loss of WHY2 decreased starch and sugar content in pericarp cells but promoted starch accumulation in leaves and seeds. These phenotypes of WHY2-overexpressing plants were enhanced in response to methyl jasmonate. Our results suggest that WHY2 in plastids, mitochondria, and the nucleus plays a vital role in alteration of carbon reallocation from maternal tissue to filial tissue.
线粒体、质体和细胞核中基因表达的协调对于植物的发育和生存至关重要。尽管 WHIRLY2(WHY2)参与线粒体基因组修复并影响线粒体基因组的 DNA 拷贝数,但 WHY2 蛋白的详细作用机制仍不清楚。在这项研究中,我们发现拟南芥衰老过程中 WHY2 在线粒体、质体和细胞核中三重定位。过表达 WHY2 增加了果皮细胞叶绿体中淀粉粒的数量,表现为部分干燥、变黄的蒴果和早衰老的叶片。因此,WHY2 蛋白可以直接激活和()基因表达,并在核内抑制基因表达,导致果皮细胞中淀粉的积累和转运发生改变。相比之下,WHY2 的缺失减少了果皮细胞中的淀粉和糖含量,但促进了叶片和种子中淀粉的积累。质体、线粒体和细胞核中 WHY2 过表达植物的这些表型在茉莉酸甲酯的作用下增强。我们的研究结果表明,质体、线粒体和细胞核中的 WHY2 在改变从母体组织到子代组织的碳再分配方面起着至关重要的作用。