Fungal specificity bottlenecks during orchid germination and development
Fungal specificity bottlenecks during orchid germination and development
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DOI：
10.1111/j.1365-294x.2008.03848.x
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发表时间：
2008-08-01
影响因子：
4.9
通讯作者：
Read, David J.
中科院分区：
文献类型：
--
作者：
Bidartondo, Martin I.;Read, David J.
真菌通过幼苗阶段的辅助生长是成千上万种通过“灰尘种子”繁殖的菌根植物物种生活史的最重要特征。“我们研究了头兰属和Epipactis属的兰花在其生命周期的三个阶段对真菌的特异性程度：（i）萌发开始，（ii）幼苗发育期间，（iii）成熟的光合植物。已知在成熟阶段，这些属的植物可以与许多真菌菌根化，这些真菌同时与邻近森林树木的根外生菌根化。早期发育阶段在多大程度上使用相同或不同的真菌套件尚不清楚。为了解决这个问题，总共有1500包含有兰花种子被埋在不同的欧洲森林网站长达3年，无论是支持或缺乏人口的helleborine兰花。收获后，通过不依赖培养的分子方法鉴定了与三个发育阶段和树根相关的真菌。虽然我们的研究结果表明，大多数真菌共生体是外生菌根，兰花之间的差异，观察在三个生命阶段的真菌的代表性。在Cephalanthera damasonium和C.在长叶的植物中，在幼苗中检测到的真菌只是在发芽种子和成熟植物中看到的更广泛范围的一个子集。在三个生活阶段中，所检测到的真菌相似，但不同的真菌谱系在幼苗萌发性能上产生差异。我们的研究结果表明，可以有一个狭窄的检查点，菌根范围在幼苗生长相对于更混杂的发芽和成熟阶段，这些植物的生活史。
Fungus-subsidized growth through the seedling stage is the most critical feature of the life history for the thousands of mycorrhizal plant species that propagate by means of 'dust seeds.' We investigated the extent of specificity towards fungi shown by orchids in the genera Cephalanthera and Epipactis at three stages of their life cycle: (i) initiation of germination, (ii) during seedling development, and (iii) in the mature photosynthetic plant. It is known that in the mature phase, plants of these genera can be mycorrhizal with a number of fungi that are simultaneously ectomycorrhizal with the roots of neighbouring forest trees. The extent to which earlier developmental stages use the same or a distinctive suite of fungi was unclear. To address this question, a total of 1500 packets containing orchid seeds were buried for up to 3 years in diverse European forest sites which either supported or lacked populations of helleborine orchids. After harvest, the fungi associated with the three developmental stages, and with tree roots, were identified via cultivation-independent molecular methods. While our results show that most fungal symbionts are ectomycorrhizal, differences were observed between orchids in the representation of fungi at the three life stages. In Cephalanthera damasonium and C. longifolia, the fungi detected in seedlings were only a subset of the wider range seen in germinating seeds and mature plants. In Epipactis atrorubens, the fungi detected were similar at all three life stages, but different fungal lineages produced a difference in seedling germination performance. Our results demonstrate that there can be a narrow checkpoint for mycorrhizal range during seedling growth relative to the more promiscuous germination and mature stages of these plants' life cycle.