Macroevolutionary persistence of heritable endosymbionts: acquisition, retention and expression of adaptive phenotypes in Spiroplasma
Macroevolutionary persistence of heritable endosymbionts: acquisition, retention and expression of adaptive phenotypes in Spiroplasma
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DOI：
10.1111/mec.13261
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发表时间：
2015-07-01
影响因子：
4.9
通讯作者：
Jaenike, John
中科院分区：
文献类型：
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作者：
Haselkorn, Tamara S.;Jaenike, John
昆虫与其兼性母系传播的内共生体之间的系统发育不一致表明，这些感染在进化上通常是短暂的。因此，许多内共生菌的长期存在必须取决于它们在新宿主物种中的定殖和传播能力。至少有17种果蝇感染了具有不同表型效应的内共生螺旋体。我们将来自三个不同分支的五株螺旋体转染到新睾丸果蝇中，以测试它们在新宿主中的传播能力。一种在黑腹果蝇（它的原生宿主）中引起雄性死亡的菌株在d.n etestacea中也有同样的作用，尽管这些宿主物种在40-60万年前就已经分化了。一株原产于d.netestacea（被称为sNeo）的菌株和另外两株螺原体poulsonii分支的菌株赋予了对黄蜂寄生的抗性，这表明这种特性可能是在这个螺原体分支中祖先产生的。相反，除了sNeo外，没有其他菌株对线虫寄生的绝育作用产生抗性，这表明线虫抗性是最近才产生的。线虫对螺原体的抗性已经赋予了对黄蜂寄生的抗性，这表明内共生体可以增加有利于其传播的性状。内共生体在新宿主中不需要宿主-共生体共同进化的一段时间就能通过母体传播并表达适应性表型，这使得这种共生体在新宿主定殖后立即传播。这对于兼性内共生体的宏观进化持久性至关重要，它们在单个宿主物种内的逗留时间相对较短。
The phylogenetic incongruence between insects and their facultative maternally transmitted endosymbionts indicates that these infections are generally short-lived evolutionarily. Therefore, long-term persistence of many endosymbionts must depend on their ability to colonize and spread within new host species. At least 17 species of Drosophila are infected with endosymbiotic Spiroplasma that have various phenotypic effects. We transinfected five strains of Spiroplasma from three divergent clades into Drosophila neotestacea to test their capacity to spread in a novel host. A strain that causes male killing in Drosophila melanogaster (its native host) also does so in D.neotestacea, even though these host species diverged 40-60mya. A strain native to D.neotestacea (designated sNeo) and the two other strains of the poulsonii clade of Spiroplasma confer resistance to wasp parasitism, suggesting that this trait may be ancestral within this clade of Spiroplasma. Conversely, no strain other than sNeo conferred resistance to the sterilizing effects of nematode parasitism, suggesting that nematode resistance is a recently derived condition. The apparent addition of nematode resistance to a Spiroplasma lineage that already confers resistance to wasp parasitism suggests endosymbionts can increase the repertoire of traits conducive to their spread. The capacity of an endosymbiont to undergo maternal transmission and express adaptive phenotypes in novel hosts, without requiring a period of host-symbiont co-evolution, enables the spread of such symbionts immediately after the colonization of a new host. This could be critical for the macroevolutionary persistence of facultative endosymbionts whose sojourn times within individual host species are relatively brief.