Temporal tracking of quantum-dot apatite across in vitro mycorrhizal networks shows how host demand can influence fungal nutrient transfer strategies.

Abstract

Arbuscular mycorrhizal fungi function as conduits for underground nutrient transport. While the fungal partner is dependent on the plant host for its carbon (C) needs, the amount of nutrients that the fungus allocates to hosts can vary with context. Because fungal allocation patterns to hosts can change over time, they have historically been difficult to quantify accurately. We developed a technique to tag rock phosphorus (P) apatite with fluorescent quantum-dot (QD) nanoparticles of three different colors, allowing us to study nutrient transfer in an in vitro fungal network formed between two host roots of different ages and different P demands over a 3-week period. Using confocal microscopy and raster image correlation spectroscopy, we could distinguish between P transfer from the hyphae to the roots and P retention in the hyphae. By tracking QD-apatite from its point of origin, we found that the P demands of the younger root influenced both: (1) how the fungus distributed nutrients among different root hosts and (2) the storage patterns in the fungus itself. Our work highlights that fungal trade strategies are highly dynamic over time to local conditions, and stresses the need for precise measurements of symbiotic nutrient transfer across both space and time.

Plant phenotyping relevance

量子ドット標識と共焦点画像解析を開発し、植物根へのリン移行および菌根内保持を時空間的に定量する手法が研究の中心であるため、植物の栄養生理状態を測定するフェノタイピング手法として含める。

Code and data availability

The paper's authors publicly deposited all data, scripts, and analysis for this study in a GitHub repository, explicitly stated in the Methods. This is a paper-specific, publicly actionable code/data asset reproducing the paper's QD-apatite phenotyping measurements and statistical analysis.