Department Organelle Biology, Biotechnology and Molecular Ecophysiology, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany.
Department Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany.
Proc Natl Acad Sci U S A. 2019 Mar 19;116(12):5665-5674. doi: 10.1073/pnas.1811661116. Epub 2019 Mar 4.
In most eukaryotes, organellar genomes are transmitted preferentially by the mother, but molecular mechanisms and evolutionary forces underlying this fundamental biological principle are far from understood. It is believed that biparental inheritance promotes competition between the cytoplasmic organelles and allows the spread of so-called selfish cytoplasmic elements. Those can be, for example, fast-replicating or aggressive chloroplasts (plastids) that are incompatible with the hybrid nuclear genome and therefore maladaptive. Here we show that the ability of plastids to compete against each other is a metabolic phenotype determined by extremely rapidly evolving genes in the plastid genome of the evening primrose Repeats in the regulatory region of (the plastid-encoded subunit of the acetyl-CoA carboxylase, which catalyzes the first and rate-limiting step of lipid biosynthesis), as well as in (a giant reading frame of still unknown function), are responsible for the differences in competitive behavior of plastid genotypes. Polymorphisms in these genes influence lipid synthesis and most likely profiles of the plastid envelope membrane. These in turn determine plastid division and/or turnover rates and hence competitiveness. This work uncovers cytoplasmic drive loci controlling the outcome of biparental chloroplast transmission. Here, they define the mode of chloroplast inheritance, as plastid competitiveness can result in uniparental inheritance (through elimination of the "weak" plastid) or biparental inheritance (when two similarly "strong" plastids are transmitted).
在大多数真核生物中，细胞器基因组优先通过母系传递，但这种基本生物学原理背后的分子机制和进化力量还远未被理解。人们认为双亲遗传促进了细胞质细胞器之间的竞争，并允许所谓的自私细胞质元件的传播。这些元件可以是快速复制或具有侵略性的叶绿体（质体），它们与杂交核基因组不兼容，因此是适应不良的。在这里，我们表明，叶绿体之间相互竞争的能力是一种代谢表型，由月见草 （一种快速进化的基因决定，这些基因位于叶绿体基因组的调控区域中 （质体编码的乙酰辅酶 A 羧化酶亚基，该酶催化脂质生物合成的第一步和限速步骤），以及在 （一个功能未知的巨大阅读框）中，这些基因的多态性影响脂质合成和最有可能的质体膜包膜的特征。这些反过来又决定了质体分裂和/或周转率，从而决定了竞争力。这项工作揭示了控制双亲叶绿体传递结果的细胞质驱动基因座。在这里，它们定义了叶绿体遗传的模式，因为质体的竞争力可以导致单亲遗传（通过消除“弱”质体）或双亲遗传（当两个类似“强”的质体被传递时）。
