L-System model for the growth of arbuscular mycorrhizal fungi, both within and outside of their host roots

Abstract

Development of arbuscular mycorrhizal fungal colonization of roots and the surrounding soil is the central process of mycorrhizal symbiosis, important for ecosystem functioning and commercial inoculum applications. To improve mechanistic understanding of this highly spatially and temporarily dynamic process, we developed a three-dimensional model taking into account growth of the roots and hyphae. It is for the first time that infection within the root system is simulated dynamically and in a spatially resolved way. Comparison between data measured in a calibration experiment and simulated results showed a good fit. Our simulations showed that the position of the fungal inoculum affects the sensitivity of hyphal growth parameters. Variation in speed of secondary infection and hyphal lifetime had a different effect on root infection and hyphal length, respectively, depending on whether the inoculum was concentrated or dispersed. For other parameters (branching rate, distance between entry points), the relative effect was the same independent of inoculum placement. The model also indicated that maximum root colonization levels well below 100%, often observed experimentally, may be a result of differential spread of roots and hyphae, besides intrinsic plant control, particularly upon localized placement of inoculum and slow secondary infection.

Mycorrhizal associations change root functionality: a 3D modelling study on competitive interactions between plants for light and nutrients

“…Functional–structural plant models typically simulate shoot architectural development and light capture (Prusinkiewicz & Lindenmayer, 1990 ; Kurth, 1994 ; Evers et al ., 2007 ) or root architectural development and nutrient uptake (Diggle, 1988 ; Pagès et al ., 1989 ; Lynch et al ., 1997 ; Dunbabin et al ., 2013 ). Yet, FSP models that explicitly combine both above‐ and belowground plant parts (Louarn & Faverjon, 2018 ; De Bauw et al ., 2020 ), or that describe the development of AMF colonization (Schnepf et al ., 2016 ; Zhou et al ., 2020 ) have seen only recent development. Here we seek to combine these elements in a novel mechanistic modelling approach that simulates competitive interactions between individual plants through the basic mechanisms of light acquisition by leaves and nutrient uptake by both roots and AMF.…”

Using evolutionary functional-structural plant modelling to understand the effect of climate change on plant communities

“…Functional-structural plant modelling is an excellent tool to simulate plants in a broad ecological context, and has been used to study a myriad of biotic interaction such as plant-plant (Bongers et al 2014;Evers and Bastiaans 2016;Faverjon et al 2019), plant-herbivore (de Vries et al 2018), plant-pathogen (Robert et al 2008;Garin et al 2014;Streit et al 2017) or plant-mycorrhizal interactions (Schnepf et al 2016;de Vries et al 2021). However, these biotic interactions are mostly simulated in isolation, and models that simulate interactions between biotic agents have only seen recent development (Douma et al 2019;de Vries et al 2021).…”

A Symbiosis Between a Dark Septate Fungus, an Arbuscular Mycorrhiza, and Two Plants Native to the Sagebrush Steppe

“…Further, the AMF inoculum was placed in a small area of the soil, which contrasts with the more disperse application of spores over the roots of transplanted seedlings. Based on simulations of hyphal growth conducted by Schnepf (2016), placement of concentrated AMF propagules increases the chances of colonization compared to a dispersed distribution.…”