Curing cytoplasmic male sterility via TALEN-mediated mitochondrial genome editing

First author: Tomohiko Kazama; Affiliations: Tohoku University (日本東北大學): Sendai, Japan

Corresponding author: Shin-ichi Arimura 

Sequence-specific nucleases are commonly used to modify the nuclear genome of plants. However, targeted modification of the mitochondrial genome of land plants has not yet been achieved. In plants, a type of male sterility called cytoplasmic male sterility (CMS) has been attributed to certain mitochondrial genes, but none of these genes has been validated by direct mitochondrial gene-targeted modification. Here, we knocked out CMS-associated genes (orf79 and orf125) of CMS varieties of rice and rapeseed, respectively, using transcription activator-like effector nucleases (TALENs) with mitochondria localization signals (mitoTALENs). We demonstrate that knocking out these genes cures male sterility, strongly suggesting that these genes are causes of CMS. Sequencing revealed that double-strand breaks induced by mitoTALENs were repaired by homologous recombination, and that during this process, the target genes and surrounding sequences were deleted. Our results show that mitoTALENs can be used to stably and heritably modify the mitochondrial genome in plants.

序列特异性的核酸通常被用来作为基因组序列修改的靶向序列。然而，陆地植物线粒体基因组靶向序列修改目前还没人可以实现。在植物中，有一种雄性不育叫做细胞质雄性不育（cytoplasmic male sterility；CMS），这种雄性不育早就被认为只有某几个线粒体基因引起的，但从来没有人能够通过直接靶向修改这几个线粒体基因证明这些基因确实作用于细胞质雄性不育。本文中，作者利用带有线粒体定位信号的类转录激活因子效应物核酸酶（mitoTALEN）成功敲除了水稻和油菜细胞质雄性不育品种的CMS相关基因，即orf79和orf79。作者发现这些基因的敲除成功治愈了这些品种的细胞质雄性不育，说明正是这几个基因作用于CMS。测序结果显示由mitoTALEN诱导的双链断裂通过同源重组被修复，但该过程靶基因及其邻近序列都被删除。本文的结果揭示了mitoTALEN能够被用来稳定并可遗传地修改植物线粒体基因组序列。

通讯：Tomohiko Kazama (http://www.agri.tohoku.ac.jp/bioadp/PukiWiki/index.php?English)

研究方向：植物适应环境的分子机制。

doi: https://doi.org/10.1038/s41477-019-0459-z

Journal: Nature Plants

Published date: July 08, 2019