About this Research Topic
Plant roots dramatically affect the soil around them driving changes in microbial communities, chemical characteristics, hydrological properties, and biogeochemical cycling. Root exudates affect the growth and composition of microbial communities in the rhizosphere, leading to vast differences in the rates of key ecological processes, such as organic matter decomposition and the transformation of major nutrients (e.g., denitrification). In addition, hydraulic redistribution can change the water status in the rhizosphere relative to bulk soil. Rhizodeposits and microbial growth also drive structural changes in soils, including the development of soil aggregates.
Mycorrhizal fungi are central players in rhizosphere dynamics; 90% of terrestrial plant species are associated with mycorrhizal fungi affecting water transport and the exchange of nutrients and carbon among organisms. Different types of mycorrhizal fungi, arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM), vary in their nutrient capture strategies, with AM fungi acquiring inorganic nutrients and ECM fungi also capable of capturing organic forms of nitrogen (N) and phosphorus (P). As ECM fungi can degrade soil organic matter to a certain degree, ecosystems with plants forming ECM fungal associations may sequester less soil carbon (C) than those dominated by AM fungi. Alternatively, ECM fungi, by directly competing with saprotrophic decomposer fungi, may inhibit overall decomposition, increasing soil C storage.
The interplay of microbial growth and competition for nutrients on soil C storage vary across time and space in seemingly idiosyncratic patterns. However, integration of natural variation in soil resources, soil mineralogy, global change pressures (e.g., N deposition, warming) and shifts in microbial consortia may resolve some of the seemingly enigmatic patterns of microbial effects on rhizospheric soil C storage at global scales.
The overall goal of this Research Topic is to identify how biotic interactions among microorganisms and plant roots affect ecosystem C and nutrient cycling.
This Research Topic will examine novel interactive effects of rhizosphere microbial communities, rhizosphere-driven soil physical and hydrological changes, and mycorrhizal fungi across forested ecosystems that influence soil C and nutrient cycling.
We anticipate manuscripts determining genetic signalling of competitive and facultative interactions in the rhizosphere, functional trait trade-offs among fungi and other rhizosphere-hosted symbionts, interactions between physical and biological processes in the rhizosphere, and modelling efforts incorporating rhizosphere and mycorrhizal processes at scales from the root to the ecosystem to the globe. This mechanistic genes-to-ecosystems approach is warranted in a changing world where phenomenological trends are unlikely to represent future ecological processes.
Sub-topics could include: the role of root exudates in soil aggregation or stable soil carbon transformations, root-microbe-soil feedbacks in response to global change factors, or effects of nutrient constraints on rhizosphere dynamics.
This list is not exhaustive and other research topics are encouraged. Manuscripts may range from original empirical and modelling research articles, to systematic reviews and meta-analyses. One perspectives manuscript will be accepted.
Keywords: Mycorrhizal, Saprotrophic, Competition, Facilitation, Rhizosphere, Carbon, Forest soil, Global change
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.