Phorophyte preference of an epiphytic orchid (Dendrobium wangliangii) is independent of orchid mycorrhizal fungi that promote seed germination
Phorophyte preference of an epiphytic orchid (Dendrobium wangliangii) is independent of orchid mycorrhizal fungi that promote seed germination
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DOI：
10.1111/1365-2745.14298
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发表时间：
2024-04
影响因子：
5.5
通讯作者：
Dake Zhao;Zongmin Mou;Erqiang Zhao;Jiamei Bai;Xue Zhang;Zihan Yuan;Ruibin Wang;Qiuxia Wang-Qiuxia-Wa
中科院分区：
文献类型：
--
作者：
Dake Zhao;Zongmin Mou;Erqiang Zhao;Jiamei Bai;Xue Zhang;Zihan Yuan;Ruibin Wang;Qiuxia Wang-Qiuxia-Wa
附生是植物之间专有的种间相互作用的一个例子，即一种植物生长在另一种植物上以获得物质支持。在依赖合适的寄主树种(芽生植物)和菌根真菌来萌发和生长的附生兰花中，观察到了对特定寄主树种的明显偏好。然而，推动这一东道主偏好的因素仍不清楚。在这项研究中，我们研究了促进幼苗发育的菌根真菌是否决定了附生兰花叶植物的喜好。首先，我们确定了这种兰花的首选寄主树种。其次，进行了体外萌发和原位萌发实验，以确定促进种子萌发的潜在真菌。最后，使用高通量测序方法评估了这些真菌在已定植寄主树种和潜在寄主树种上的分布，包括尚未被兰花定植的寄主树种的单个树木和生长在已定殖树木附近的另一物种的树木。王良石斛对壳斗科植物表现出一定的喜好。从寄主树皮中提取的两种镰刀菌被鉴定为促进种子萌发的主要真菌。成功的原球茎形成和幼苗发育仅在优先选择的植根植物上观察到。真菌群落分析进一步表明，两种镰刀菌均为赤霉菌。这种附生兰花的寄主选择性不受适宜菌根真菌分布的限制。综合：对于依靠菌根真菌成功更新幼苗的附生植物，我们得出的结论是，强烈的附生-藻类联合并不是由于菌根真菌的有限分布，而是更可能是藻类环境中固有的其他因素的结果。
Epiphytism is an example of an obligate interspecific interaction between plants, where a plant species grows on another plant species for physical support. In epiphytic orchids that rely on suitable host tree species (phorophytes) and mycorrhizal fungi for germination and growth, a distinct preference has been observed for particular host tree species. However, the factors driving this host preference remain unclear. In this study, we investigated whether mycorrhizal fungi that promote seedling development determine the preference of phorophytes in the epiphytic orchid Dendrobium wangliangii. First, we identified the preferred host tree species for this orchid. Next, in vitro and in situ germination experiments were conducted to identify potential fungi that promote seed germination. Finally, high‐throughput sequencing was used to assess the distribution of these fungi on both colonized host trees and potential host trees, including individual trees of the host species not yet colonized by the orchid and trees of another species growing in the vicinity of a colonized tree. Dendrobium wangliangii exhibited a preference for trees within the Fagaceae family. Two Fusarium species from the bark of host trees were identified as the primary fungi that promote seed germination. Successful protocorm formation and seedling development were observed exclusively on preferred phorophytes. Fungal community analyses further indicated that both Fusarium spp. occurred on all potential host trees, suggesting that the host preference of this epiphytic orchid is not constrained by the distribution of suitable mycorrhizal fungi. Synthesis: Regarding the epiphytes that depend on mycorrhizal fungi for successful seedling recruitment, we conclude that strong epiphyte–phorophyte associations do not arise from the limited distribution of mycorrhizal fungi but are more likely the result of other factors inherent in the phorophyte environment.