Bentolila Stephane, Alfonso Antonio A, Hanson Maureen R
Department of Molecular Biology and Genetics, 323 Biotechnology Building, Cornell University, Ithaca, NY 14853, USA.
Proc Natl Acad Sci U S A. 2002 Aug 6;99(16):10887-92. doi: 10.1073/pnas.102301599. Epub 2002 Jul 22.
Known in over 150 species, cytoplasmic male sterility is encoded by aberrant mitochondrial genes that prevent pollen development. The RNA- or protein-level expression of most of the mitochondrial genes encoding cytoplasmic male sterility is altered in the presence of one or more nuclear genes called restorers of fertility that suppress the male-sterile phenotype. Cytoplasmic male sterility/restorer systems have been proven to be an invaluable tool in the production of hybrid seeds. Despite their importance for both the production of major crops such as rice and sunflower and the study of organelle/nuclear interactions in plants, none of the nuclear fertility-restorer genes that reduce the expression of aberrant mitochondrial proteins have previously been cloned. Here we report the isolation of a gene directly involved in the control of the expression of a cytoplasmic male sterility-encoding gene. The Petunia restorer of fertility gene product is a mitochondrially targeted protein that is almost entirely composed of 14 repeats of the 35-aa pentatricopeptide repeat motif. In a nonrestoring genotype we identified a homologous gene that exhibits a deletion in the promoter region and is expressed in roots but not in floral buds.
细胞质雄性不育在150多个物种中存在，由异常的线粒体基因编码，这些基因会阻止花粉发育。在存在一个或多个称为育性恢复基因的核基因时，大多数编码细胞质雄性不育的线粒体基因的RNA或蛋白质水平表达会发生改变，这些核基因会抑制雄性不育表型。细胞质雄性不育/恢复系统已被证明是杂交种子生产中一种非常有价值的工具。尽管它们对于水稻和向日葵等主要作物的生产以及植物细胞器/核相互作用的研究都很重要，但此前尚未克隆出任何能降低异常线粒体蛋白表达的核育性恢复基因。在此，我们报告了一个直接参与控制细胞质雄性不育编码基因表达的基因的分离。矮牵牛育性恢复基因产物是一种定位于线粒体的蛋白质，几乎完全由35个氨基酸的五肽重复基序的14个重复序列组成。在一个非恢复基因型中，我们鉴定出一个同源基因，该基因在启动子区域存在缺失，在根中表达但在花芽中不表达。
