Functional kleptoplasty in a limapontioidean genus: phylogeny, food preferences and photosynthesis in Costasiella, with a focus on C. ocellifera (Gastropoda: Sacoglossa)
Functional kleptoplasty in a limapontioidean genus: phylogeny, food preferences and photosynthesis in Costasiella, with a focus on C. ocellifera (Gastropoda: Sacoglossa)
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DOI：
10.1093/mollus/eyu026
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发表时间：
2014-12-01
影响因子：
1.2
通讯作者：
Waegele, Heike
中科院分区：
文献类型：
--
作者：
Christa, Gregor;Gould, Sven B.;Waegele, Heike
囊舌内的功能性kleptoplasty（隔离和保留功能性质体）的进化和起源仍然存在争议。虽然一些作者认为它是一个含副足类的板鳃总科的突触形态，但其他人认为它更早起源于更具包容性的板鳃科。后者是支持的kleptoplasts在Costasiella ocellifera，Limapontioidea的ceras-bearing成员的存在下，在其中他们保持功能几个星期，并固定CO2。然而，Costasiella的系统发育关系，特别是关于Plakobranchoidea，还没有得到令人满意的证明，光合作用的能力和光合作用的重要性，在属内仍然缺乏研究。本研究分析了五种Costasiella的系统发育位置、光合作用活性及其在饥饿条件下的生存重要性。单眼亚目。我们证明，Costasiella是Limapontioidea的基础成员，但最终结论的起源功能kleptoplasty内Sacoglossa仍然是不可能的。三种Costasiella物种保持功能性叶绿体（其中C. ocellifera具有较长的滞留期，C. kuroshimae和C. sp. 1短期保留），并共同形成一个单系群，主要以Avrainvillea为食。这两个非光合作用的物种，C. nonatoi和C. sp. 2，代表姐妹分支，以Avrainvillea以外的藻类为食。有趣的是，C。ocellifera生存在非光合条件下的最低38天，表明光合作用可能不是必需的，以生存饥饿。这些发现支持了我们之前的建议，即在饥饿期间，kleptoplasts主要代表一种储藏室，其功能可能受益于持续的光合作用。
The evolution and origin of functional kleptoplasty (sequestration and retention of functional plastids) within the Sacoglossa is still controversial. While some authors have suggested that it is a synapomorphy of the parapodia-bearing Plakobranchoidea, others have suggested an earlier origin at the base of the more inclusive clade Plakobranchacea. The latter is supported by the presence of kleptoplasts in Costasiella ocellifera, a ceras-bearing member of Limapontioidea, in which they remain functional for several weeks and fix CO2. However, the phylogenetic relationships of Costasiella, especially with regard to the Plakobranchoidea, have not been satisfactorily demonstrated, and the photosynthetic ability and the importance of photosynthesis within the genus remain poorly studied. In this study we analyse the phylogenetic position, photosynthetic activity and importance of photosynthesis for survival during starvation of five Costasiella species, but focusing on C. ocellifera. We demonstrate that Costasiella is a basal member of the Limapontioidea, however a final conclusion on the origin of functional kleptoplasty within Sacoglossa is still not possible. Three Costasiella species maintain functional chloroplasts (of which C. ocellifera shows long-term retention, and both C. kuroshimae and C. sp. 1 short-term retention) and together form a monophyletic group, feeding mainly on Avrainvillea. The two nonphotosynthetic species, C. nonatoi and C. sp. 2, represent the sister clade and feed on algae other than Avrainvillea. Intriguingly, C. ocellifera survived under nonphotosynthetic conditions for a minimum of 38 d, demonstrating that photosynthates may not be essential in order to survive starvation. These findings support our previous suggestion that during starvation kleptoplasts primarily represent a sort of larder, whose function might benefit from ongoing photosynthesis.