Independent recruitment of saprotrophic fungi as mycorrhizal partners by tropical achlorophyllous orchids
Independent recruitment of saprotrophic fungi as mycorrhizal partners by tropical achlorophyllous orchids
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DOI：
10.1111/j.1469-8137.2009.02987.x
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发表时间：
2009-01-01
期刊：
影响因子：
9.4
通讯作者：
Selosse, Marc-Andre
中科院分区：
文献类型：
--
作者：
Martos, Florent;Dulormne, Maguy;Selosse, Marc-Andre
真菌异养型兰花通过转变为无绿叶植物并从它们的菌根真菌那里获得碳，已经适应了荫蔽的森林林下植物。在温带森林中，它们以高度特异性的方式与附近树木上的真菌形成外生菌根，并利用树木的光合作用。然而，许多热带雨林缺乏外生菌根真菌，有证据表明，一些热带亚洲物种与saprotrophic fungies.To调查这在不同的地理和系统发育的背景下，我们确定了菌根真菌支持两个热带mycoheterotrophic兰花从马斯克林（印度洋）和加勒比群岛。我们通过测量天然氮（15 N）和碳（13 C）的丰度来测试它们可能的碳源。发现了腐生性担子菌：天麻与木材腐烂的树脂菌属（Hymenochaetales）有关; Wullschlaegelia aphylla与凋落物腐烂的裸果木属和小菇属物种有关，它们的根型将兰花的根与凋落物联系起来。15 N和13 C的丰度使从枯木到G的食物链变得合理。similis和从枯叶到W.我们建议，在热带雨林，但不是在大多数温带森林的温度和湿度，可能有利于足够的腐殖活动，以支持发展的mycoheterotrophs。通过扩大菌根真菌的光谱和真菌异养兰花的特异性水平，这项研究为热带地区的兰花和菌根生物学提供了新的见解。New Phytologist（2009）doi：10.1111/j.1469-8137.2009.02987.x。
P>Mycoheterotrophic orchids have adapted to shaded forest understory by shifting to achlorophylly and receiving carbon from their mycorrhizal fungi. In temperate forests, they associate in a highly specific way with fungi forming ectomycorrhizas on nearby trees, and exploiting tree photosynthates. However, many rainforests lack ectomycorrhizal fungi, and there is evidence that some tropical Asiatic species associate with saprotrophic fungi.To investigate this in different geographic and phylogenetic contexts, we identified the mycorrhizal fungi supporting two tropical mycoheterotrophic orchids from Mascarene (Indian Ocean) and Caribbean islands. We tested their possible carbon sources by measuring natural nitrogen (15N) and carbon (13C) abundances.Saprotrophic basidiomycetes were found: Gastrodia similis associates with a wood-decaying Resinicium (Hymenochaetales); Wullschlaegelia aphylla associates with both litter-decaying Gymnopus and Mycena species, whose rhizomorphs link orchid roots to leaf litter. The 15N and 13C abundances make plausible food chains from dead wood to G. similis and from dead leaves to W. aphylla.We propose that temperature and moisture in rainforests, but not in most temperate forests, may favour sufficient saprotrophic activity to support development of mycoheterotrophs. By enlarging the spectrum of mycorrhizal fungi and the level of specificity in mycoheterotrophic orchids, this study provides new insights on orchid and mycorrhizal biology in the tropics.New Phytologist (2009)doi: 10.1111/j.1469-8137.2009.02987.x.