Schnepf A, Leitner D, Schweiger P F, Scholl P, Jansa J
Forschungszentrum Juelich GmbH, Institute of Bio- and Geosciences, IBG-3: Agrosphere, 52425 Juelich, Germany
Computational Science Center, University of Vienna, Oskar Morgenstern-Platz 1, 1090 Vienna, Austria.
J R Soc Interface. 2016 Apr;13(117). doi: 10.1098/rsif.2016.0129.
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.
丛枝菌根真菌在根及周围土壤中的定殖发育是菌根共生的核心过程，对生态系统功能和商业接种剂应用具有重要意义。为了增进对这一高度时空动态过程的机理理解，我们开发了一个三维模型，该模型考虑了根和菌丝的生长。这是首次以空间分辨的方式动态模拟根系内的感染情况。校准实验中测量的数据与模拟结果之间的比较显示拟合良好。我们的模拟表明，真菌接种剂的位置会影响菌丝生长参数的敏感性。二次感染速度和菌丝寿命的变化分别对根感染和菌丝长度有不同影响，这取决于接种剂是集中还是分散。对于其他参数（分支率、进入点之间的距离），相对影响与接种剂的放置位置无关，保持一致。该模型还表明，实验中经常观察到的远低于100%的最大根定殖水平，除了植物自身的控制因素外，尤其是在接种剂局部放置和二次感染缓慢的情况下，可能是根和菌丝不同扩散的结果。
