ABSTRACT

Fungal metabolic carbon acquisition and its subsequent partitioning between biomass production and respiration, i.e. the carbon-use efficiency (CUE), are central parameters in biogeochemical modeling. However, current available techniques for estimating these parameters are all associated with practical and theoretical shortcomings, making assessments unreliable. Gene expression analyses hold the prospect of phenotype prediction by indirect means, providing new opportunities to obtain information about metabolic priorities. We cultured four different fungal isolates (Chalara longipes, Laccaria bicolor, Serpula lacrymans and Trichoderma harzianum) in liquid media with contrasting nitrogen availability and measured growth rates and respiration to calculate CUE. By relating gene expression markers to measured carbon fluxes, we identified genes coding for 1,3-β-glucan synthase and 2-oxoglutarate dehydrogenase as suitable markers for growth and respiration, respectively, capturing both intraspecific variation as well as within-strain variation dependent on growth medium. A transcript index based on these markers correlated significantly with differences in CUE between the fungal isolates. Our study paves the way for the use of these markers to assess differences in growth, respiration and CUE in natural fungal communities, using metatranscriptomic or the RT-qPCR approach.

中文翻译：

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真菌生长、呼吸和碳利用效率的转录组学标记

摘要

真菌代谢碳的获取及其随后在生物质生产和呼吸之间的分配，即碳利用效率 (CUE)，是生物地球化学建模的核心参数。然而，目前用于估计这些参数的可用技术都存在实践和理论缺陷，使得评估不可靠。基因表达分析为通过间接方式预测表型提供了前景，为获取有关代谢优先级的信息提供了新的机会。我们培养四种不同的真菌分离（Chalara长柄日光菊，双色蜡蘑，龙介虫长吻和哈茨木霉) 在具有对比氮可用性和测量的生长速率和呼吸的液体培养基中计算 CUE。通过将基因表达标记与测量的碳通量相关联，我们确定了编码 1,3-β-葡聚糖合酶和 2-酮戊二酸脱氢酶的基因分别作为生长和呼吸的合适标记，捕获了种内变异和菌株内变异依赖在生长培养基上。基于这些标记的转录指数与真菌分离物之间的 CUE 差异显着相关。我们的研究为使用这些标记物评估天然真菌群落中生长、呼吸和 CUE 的差异铺平了道路，使用元转录组学或 RT-qPCR 方法。