Somatic incompatibility and genetic structure of fungal crops in sympatric Atta colombica and Acromyrmex echinatior leaf-cutting ants.
Somatic incompatibility and genetic structure of fungal crops in sympatric Atta colombica and Acromyrmex echinatior leaf-cutting ants.
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DOI：
10.1016/j.funeco.2015.08.003
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发表时间：
2015-12
期刊：
影响因子：
2.9
通讯作者：
Boomsma JJ
中科院分区：
文献类型：
--
作者：
Kooij PW;Poulsen M;Schiøtt M;Boomsma JJ
有义务的互惠共生依赖于确保宿主-共生体承诺的机制，以最大化宿主利益并防止共生体作弊。以前的研究表明，体细胞不亲和性与巴拿马Acromyrmex切叶蚂蚁的真菌共生体之间基于中性标记的遗传距离有关，但这种关系在更广泛的范围内适用的程度尚不清楚。在这里，我们表明，无论是否使用中性微卫星或AFLP标记，遗传距离都可以准确地预测棘突Acromyrmex echinatior共生体的体细胞不亲和性，但在共域的Atta Colombica群体中，这种相关性较弱或不存在。进一步的分析表明，Achechinatior和A.colombica保持的共生体分支可能代表着不同的基因库，因此中性标记不太可能与经历了不同选择制度的不亲和基因座具有类似的相关性。我们认为，由阿塔蜂王建立的进化派生的屏蔽群可能已经消除了阿塔真菌中强烈不相容的选择，因为这种情况使得共生体互换的可能性比在Acromyrmex中低得多，在Acromyrmex中，由于蜂王必须在第一批工蚁出现之前觅食，所以在Acromyrmex中，初生巢保持开放。
Obligate mutualistic symbioses rely on mechanisms that secure host-symbiont commitments to maximize host benefits and prevent symbiont cheating. Previous studies showed that somatic incompatibilities correlate with neutral-marker-based genetic distances between fungal symbionts of Panamanian Acromyrmex leaf-cutting ants, but the extent to which this relationship applies more generally remained unclear. Here we showed that genetic distances accurately predicted somatic incompatibility for Acromyrmex echinatior symbionts irrespective of whether neutral microsatellites or AFLP markers were used, but that such correlations were weaker or absent in sympatric Atta colombica colonies. Further analysis showed that the symbiont clades maintained by A. echinatior and A. colombica were likely to represent separate gene pools, so that neutral markers were unlikely to be similarly correlated with incompatibility loci that have experienced different selection regimes. We suggest that evolutionarily derived claustral colony founding by Atta queens may have removed selection for strong incompatibility in Atta fungi, as this condition makes the likelihood of symbiont swaps much lower than in Acromyrmex, where incipient nests stay open because queens have to forage until the first workers emerge.