Investigations on mycorrhizal associates and nutritional resources of mycoheterotrophic orchids in Taiwan

台湾菌根异养兰花的菌根伴生及营养资源调查

• 批准号: 405009566
• 负责人: Professor Dr. Gerhard Gebauer
• 金额: --
• 依托单位: National Science and Technology Council (NSTC)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/405009566?language=en
• 关键词: Investigations; mycorrhizal; associates; nutritional; resources

About 1 % of all orchid species is achlorophyllous and depends on mycorrhizal partners for carbon and mineral nutrient supplies throughout their entire life cycle. These achlorophyllous orchids are known as mycoheterotrophic plants. In temperate and boreal forests, mycoheterotrophic orchids associate with narrow clades of ectomycorrhizal fungi and obtain photosynthates from neighbouring trees through underground mycorrhizal networks. In contrast to these findings, in tropical and subtropical forests a couple of mycoheterotrophic orchids have been reported to associate with saprotrophic non-rhizoctonia fungi and obtain nutrients through their ability of wood- or litter-decay. Nonetheless, also ectomycorrhizal-associated mycoheterotrophic orchids have been reported for subtropical forests. Thus, for subtropical and tropical forests a co-occurrence of mycoheterotrophic orchids associated with wood or litter-decay fungi and with ectomycorrhizal fungi is likely. As compared to the temperate region (e.g. two mycoheterotrophic orchid species in entire Europe), a great diversity of mycoheterotrophic orchids (more than 120 species) occurs in tropical and subtropical Asia. In Taiwan, among the ca. 400 native orchids, more than 50 fully MH orchids of 16 genera were recorded. The fungal partners and nutritional modes of most mycoheterotrophic orchids in Taiwan are still unknown. In this joint call project of MOST-DFG we will use molecular methods together with a multi-element stable isotope natural abundance approach and tracer applications to investigate a wide range of mycoheterotrophic orchid species from six genera and to address the following objectives:(1) We are going to identify the fungal associates of more than 20 mycoheterotrophic orchid species.(2) We are going to compare the fungal diversity (OTUs) in mycorrhiza of these orchids using metagenomic analysis.(3) To reveal their nutritional resources, we are going to analyze carbon, nitrogen, hydrogen and oxygen stable isotope natural abundances of mycoheterotrophic orchids associated with different fungal groups in various forest types and mountain elevation zones and compare these isotope abundances to co-occurring fully autotrophic plants.From this project we expect to obtain the following results:(1) We will identify the mycorrhizal associates of the target orchid species studied in this project and understand the mycorrhizal diversity, specificity and distribution patterns of native mycoheterotrophic orchids in Taiwan.(2) We will trace the nutritional resources and nutrient flows of the target orchid species associated with different mycorrhizal partners and occurring in various habitats from high/low elevation and different forest types.

大约1%的兰花是非绿叶植物，在其整个生命周期中依赖菌根伙伴提供碳和矿物质养分。这些非绿叶兰花被称为真菌异养植物。在温带和北方森林中，真菌异养兰花与狭窄的外生菌根真菌共生，并通过地下菌根网络从邻近树木获得光合作用。与这些发现相反的是，在热带和亚热带森林中，据报道有几种真菌异养兰花与腐生性非丝核菌真菌有关，并通过它们的木材或凋落物腐烂能力获得营养。尽管如此，亚热带森林中也有与外生菌根相关的异养菌兰花的报道。因此，对于亚热带和热带森林，真菌异养兰花很可能与木材或凋落物腐烂真菌和外生菌根真菌共存。与温带地区相比(例如，整个欧洲有两种真菌异养兰花)，热带和亚热带亚洲出现了大量的真菌异养兰花(超过120种)。在台湾约四百株的原生兰花中，有十六属五十多株完全MH兰花。台湾大多数真菌异养兰花的真菌配对和营养模式尚不清楚。在MOST-DFG的这个联合呼吁项目中，我们将使用分子方法、多元素稳定同位素自然丰度方法和示踪剂应用来调查来自6个属的广泛的真菌异养兰花物种，并解决以下目标：(1)我们将鉴定20多个真菌异养兰花物种的真菌伴生体。(2)我们将利用元基因组分析来比较这些兰花菌根中的真菌多样性(OTUS)。(3)为了揭示它们的营养来源，我们将分析碳、氮、透过本计画，我们将获得以下结果：(1)鉴定本计画中目标兰科植物的菌根共生体，了解台湾原生异养兰科植物的菌根多样性、专一性及分布型态。(2)追踪不同菌根伙伴的兰科兰科植物在不同生境、不同海拔及不同森林类型的营养资源与营养流向。