Phosphorus and carbon availability regulate structural composition and complexity of AM fungal mycelium
Phosphorus and carbon availability regulate structural composition and complexity of AM fungal mycelium
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DOI：
10.1007/s00572-014-0557-8
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发表时间：
2014-01
期刊：
影响因子：
3.9
通讯作者：
O. Olsson;P. Olsson;Edith C. Hammer
中科院分区：
文献类型：
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作者：
O. Olsson;P. Olsson;Edith C. Hammer
由于丛枝菌根（AM）真菌的专性生物营养性质，其菌丝体的结构组成和复杂性的调节尚不清楚。本研究的目的是研究根部碳 (C) 利用率和真菌磷 (P) 利用率高和低时的根外菌丝体结构。我们使用 AM 真菌不规则根噬菌（以前称为根内球霉）的单细胞培养物，以转化的胡萝卜根作为培养系统中的宿主，该系统包括一个无根隔室，根外菌丝体可以在其中生长。我们发现，高碳利用率增加了菌丝长度、孢子产量以及单个菌丝体内的吻合形成。高磷利用率增加了分支吸收结构的形成，并减少了孢子产量和转行菌丝的总长度。菌丝体的复杂性（如其分形维数所示）随着 C 和 P 利用率的提高而增加。结果表明，低磷利用率诱导的生长模式反映了对磷和碳的觅食。当磷利用率低时，AM根的低碳利用率仍然可以支持菌丝体的探索性发育。这些发现有助于我们更好地了解 AM 真菌在高磷输入的生态系统中和/或当植物受到遮荫、放牧或任何降低植物光合作用能力的管理实践时的发育。
The regulation of the structural composition and complexity of the mycelium of arbuscular mycorrhizal (AM) fungi is not well understood due to their obligate biotrophic nature. The aim of this study was to investigate the structure of extraradical mycelium at high and low availability of carbon (C) to the roots and phosphorus (P) to the fungus. We used monoxenic cultures of the AM fungusRhizophagus irregularis(formerlyGlomus intraradices) with transformed carrot roots as the host in a cultivation system including a root-free compartment into which the extraradical mycelium could grow. We found that high C availability increased hyphal length and spore production and anastomosis formation within individual mycelia. High P availability increased the formation of branched absorbing structures and reduced spore production and the overall length of runner hyphae. The complexity of the mycelium, as indicated by its fractal dimensions, increased with both high C and P availability. The results indicate that low P availability induces a growth pattern that reflects foraging for both P and C. Low C availability to AM roots could still support the explorative development of the mycelium when P availability was low. These findings help us to better understand the development of AM fungi in ecosystems with high P input and/or when plants are subjected to shading, grazing or any management practice that reduces the photosynthetic ability of the plant.