可移动遗传元件在可遗传内共生菌进化持久性中的作用。
The role of mobile genetic elements in evolutionary longevity of heritable endobacteria.
作者信息
Naito Mizue, Pawlowska Teresa E
机构信息
Graduate Field of Microbiology, Cornell University, Ithaca, NY, USA; Present address: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology, Cornell University , Ithaca, NY, USA.
出版信息
Mob Genet Elements. 2015 Dec 30;6(1):e1136375. doi: 10.1080/2159256X.2015.1136375. eCollection 2016 Jan-Feb.
The movement of mobile genetic elements (MGEs), including bacteriophages, insertion sequence (IS) elements, and integrative and conjugative elements (ICEs) can have profound effects on bacterial evolution by introducing novel genes, or disrupting the existing ones. Obligate endobacteria are a distinctive group of bacteria that reside within the intracellular compartments of their eukaryotic hosts. Many obligate endobacteria are reproductively dependent on their hosts. Vertical transmission, in addition to degenerative genome contraction and loss of MGEs, makes heritable endobacteria vulnerable to Muller's ratchet, a process that jeopardizes evolutionary longevity of small populations. Mycoplasma-related endobacteria (MRE) are ancient heritable endosymbionts of arbuscular mycorrhizal fungi. Their genomes harbour numerous MGEs. To explore the significance of MGEs in the evolution of MRE and other obligate endobacteria, we analyze the impact of transmission mode, recombination, and evolutionary age on the maintenance of MGEs. Furthermore, we discuss the ability of MGEs to act as sites of gene conversion and recombination in endobacterial genomes. We propose that MGEs are important instruments of genome shuffling, contributing to population heterogeneity and evolutionary longevity in heritable obligate endobacteria.
包括噬菌体、插入序列（IS）元件以及整合与接合元件（ICE）在内的可移动遗传元件（MGEs）的移动，可通过引入新基因或破坏现有基因，对细菌进化产生深远影响。专性内生菌是一类独特的细菌群体，它们寄生于真核宿主细胞内的区室中。许多专性内生菌在繁殖上依赖于其宿主。垂直传播，再加上基因组的退化性收缩和MGEs的丢失，使得可遗传的内生菌容易受到穆勒棘轮效应的影响，这一过程会危及小种群的进化寿命。支原体相关内生菌（MRE）是丛枝菌根真菌古老的可遗传内共生体。它们的基因组含有大量MGEs。为了探究MGEs在MRE及其他专性内生菌进化中的意义，我们分析了传播模式、重组和进化年龄对MGEs维持的影响。此外，我们还讨论了MGEs在细菌基因组中作为基因转换和重组位点的能力。我们认为，MGEs是基因组重排的重要工具，有助于可遗传专性内生菌的种群异质性和进化寿命。
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