Host sanctions and the legume-rhizobium mutualism
Host sanctions and the legume-rhizobium mutualism
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DOI：
10.1038/nature01931
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发表时间：
2003-09-04
期刊：
影响因子：
64.8
通讯作者：
Denison, RF
中科院分区：
文献类型：
--
作者：
Kiers, ET;Rousseau, RA;Denison, RF
解释物种之间的互惠合作仍然是进化生物学最大的问题之一（1-4）。为什么共生体为主机提供昂贵的服务，间接地使共享同一主机的竞争对手受益？宿主对共生体性能的监控和对“作弊者”的制裁可以稳定互利共生（5，6）。在这里，我们表明，大豆惩罚根瘤菌，不能固定N-2内的根瘤。我们阻止了一个正常的互惠共生根瘤菌株合作（固定N-2），通过更换空气与N-2-免费的气氛（Ar：O-2）。一系列实验在三个空间尺度（整个植物，半根系和单个根瘤）表明，强迫不合作（类似于作弊）减少了约50%的根瘤菌的繁殖成功。非侵入性监测牵连减少O-2供应作为一种可能的机制制裁欺骗根瘤菌。更一般地说，一方或双方的这种制裁可能对稳定广泛的互利共生关系很重要。
Explaining mutualistic cooperation between species remains one of the greatest problems for evolutionary biology(1-4). Why do symbionts provide costly services to a host, indirectly benefiting competitors sharing the same individual host? Host monitoring of symbiont performance and the imposition of sanctions on 'cheats' could stabilize mutualism(5,6). Here we show that soybeans penalize rhizobia that fail to fix N-2 inside their root nodules. We prevented a normally mutualistic rhizobium strain from cooperating (fixing N-2) by replacing air with an N-2-free atmosphere (Ar:O-2). A series of experiments at three spatial scales (whole plants, half root systems and individual nodules) demonstrated that forcing non-cooperation (analogous to cheating) decreased the reproductive success of rhizobia by about 50%. Non-invasive monitoring implicated decreased O-2 supply as a possible mechanism for sanctions against cheating rhizobia. More generally, such sanctions by one or both partners may be important in stabilizing a wide range of mutualistic symbioses.