Merckx Vincent, Bidartondo Martin I
Laboratory of Plant Systematics, K. U. Leuven, Kasteelpark Arenberg 31, PO Box 2437, 3001 Leuven, Belgium.
Proc Biol Sci. 2008 May 7;275(1638):1029-35. doi: 10.1098/rspb.2007.1622.
The ancient arbuscular mycorrhizal association between the vast majority of plants and the fungal phylum Glomeromycota is a dominant nutritional mutualism worldwide. In the mycorrhizal mutualism, plants exchange photosynthesized carbohydrates for mineral nutrients acquired by fungi from the soil. This widespread cooperative arrangement is broken by 'cheater' plant species that lack the ability to photosynthesize and thus become dependent upon three-partite linkages (cheater-fungus-photosynthetic plant). Using the first fine-level coevolutionary analysis of mycorrhizas, we show that extreme fidelity towards fungi has led cheater plants to lengthy evolutionary codiversification. Remarkably, the plants' evolutionary history closely mirrors that of their considerably older mycorrhizal fungi. This demonstrates that one of the most diffuse mutualistic networks is vulnerable to the emergence, persistence and speciation of highly specific cheaters.
绝大多数植物与球囊菌门真菌之间古老的丛枝菌根共生关系，是全球范围内一种占主导地位的营养共生关系。在菌根共生关系中，植物用光合作用产生的碳水化合物，交换真菌从土壤中获取的矿物质营养。这种广泛存在的合作关系被一些“欺骗性”植物物种打破，这些植物缺乏光合作用的能力，因此依赖三方联系（欺骗性植物-真菌-光合植物）。通过对菌根进行首次精细层面的协同进化分析，我们发现对真菌的极端忠诚导致欺骗性植物经历了漫长的进化共同多样化过程。值得注意的是，这些植物的进化历史与它们古老得多的菌根真菌的进化历史密切相似。这表明，最广泛分布的共生网络之一容易受到高度特异性欺骗者的出现、持续存在和物种形成的影响。
