EVOLUTIONARY STABILITY IN A 400-MILLION-YEAR-OLD HERITABLE FACULTATIVE MUTUALISM
EVOLUTIONARY STABILITY IN A 400-MILLION-YEAR-OLD HERITABLE FACULTATIVE MUTUALISM
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DOI：
10.1111/j.1558-5646.2012.01611.x
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发表时间：
2012-08-01
期刊：
影响因子：
3.3
通讯作者：
Pawlowska, Teresa E.
中科院分区：
文献类型：
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作者：
Mondo, Stephen J.;Toomer, Kevin H.;Pawlowska, Teresa E.
许多真核生物与可遗传的内细菌相互作用以满足不同的代谢需要。其中一些相互作用是兼性共生，其中一个伙伴对另一个伙伴并不重要。兼性共生被认为是沿着进化轨迹向专性关系过渡的阶段。我们在Ca中测试了这一进化理论预测。大孢子球囊霉，丛枝菌根真菌（球囊霉门）的非必需内共生体。我们发现可遗传的兼性互惠现象既可以是古老的，也可以是进化稳定的。我们检测到的合作伙伴之间的显着模式的共同分歧，我们只希望在强制协会。使用codifferentiating合作伙伴对和真菌化石记录，我们建立了GlomeromycotaGlomeribacter共生至少有4亿年的历史。尽管有明显的共趋异的迹象，我们确定的Glomeribacter内细菌进行重组和宿主转换，显示模式表明该协会是不是朝着相互依赖的发展。我们假设，低频率的重组在遗传内共生体与主机切换稳定兼性互惠在延长的进化时间。
Many eukaryotes interact with heritable endobacteria to satisfy diverse metabolic needs. Some of these interactions are facultative symbioses, in which one partner is not essential to the other. Facultative symbioses are expected to be transitional stages along an evolutionary trajectory toward obligate relationships. We tested this evolutionary theory prediction in Ca. Glomeribacter gigasporarum, nonessential endosymbionts of arbuscular mycorrhizal fungi (Glomeromycota). We found that heritable facultative mutualisms can be both ancient and evolutionarily stable. We detected significant patterns of codivergence between the partners that we would only expect in obligate associations. Using codiverging partner pairs and the fungal fossil record, we established that the GlomeromycotaGlomeribacter symbiosis is at least 400 million years old. Despite clear signs of codivergence, we determined that the Glomeribacter endobacteria engage in recombination and host switching, which display patterns indicating that the association is not evolving toward reciprocal dependence. We postulate that low frequency of recombination in heritable endosymbionts together with host switching stabilize facultative mutualisms over extended evolutionary times.