Interplant carbon and nitrogen transfers mediated by common arbuscular mycorrhizal networks: beneficial pathways for system functionality

Abstract

Arbuscular mycorrhizal fungi (AMF) are ubiquitous in soil and form nutritional symbioses with ~80% of vascular plant species, which significantly impact global carbon (C) and nitrogen (N) biogeochemical cycles. Roots of plant individuals are interconnected by AMF hyphae to form common AM networks (CAMNs), which provide pathways for the transfer of C and N from one plant to another, promoting plant coexistence and biodiversity. Despite that stable isotope methodologies (13C, 14C and 15N tracer techniques) have demonstrated CAMNs are an important pathway for the translocation of both C and N, the functioning of CAMNs in ecosystem C and N dynamics remains equivocal. This review systematically synthesizes both laboratory and field evidence in interplant C and N transfer through CAMNs generated through stable isotope methodologies and highlights perspectives on the system functionality of CAMNs with implications for plant coexistence, species diversity and community stability. One-way transfers from donor to recipient plants of 0.02-41% C and 0.04-80% N of recipient C and N have been observed, with the reverse fluxes generally less than 15% of donor C and N. Interplant C and N transfers have practical implications for plant performance, coexistence and biodiversity in both resource-limited and resource-unlimited habitats. Resource competition among coexisting individuals of the same or different species is undoubtedly modified by such C and N transfers. Studying interplant variability in these transfers with 13C and 15N tracer application and natural abundance measurements could address the eco physiological significance of such CAMNs in sustainable agricultural and natural ecosystems.

Understanding the mechanisms of nutrient transfer between Arbuscular Mycorrhizal Fungi (AMF) and Host Plants

“…The authors strive to elucidate the functionality of these transitions and their implications for plant cohabitation, species diversity, and community stability. Their findings demonstrate that CAMNs significantly influence one-way changes in C and N, ranging from 0.02% to 41% for C and 0.04% to 80% for N [33]. C and N transition through CAMNs significantly affect plant functionality and biodiversity.…”

“…Furthermore, the transfer of C and N through CAMNs has implications for species diversity. They [33] observed that higher levels of resource sharing lead to increased species richness within communities. This is because plants with lower resource availability can benefit from those with higher availability through these interplant transfers.…”

“…Additionally, community stability is greatly influenced by CAMN-mediated nutrient transfers. By facilitating nutrient redistribution, CAMNs contribute to a more balanced nutrient supply across different plant individuals within a community [33]. This balance enhances overall ecosystem stability by reducing fluctuations in nutrient availability.…”

Diversity, Distribution, and applications of arbuscular mycorrhizal fungi in the Arabian Peninsula

“…Hence, it is not surprising why AMF species are profoundly located in plants found in arid and desert climates ( Gollotte et al, 2004 , Ma et al, 2022a ). However, helping plants with water or providing C sources to fungi is an oversimplification of the structure–function correlation with respect to host interactions ( Luo et al, 2023 , Newsham et al, 1995 ). The AMF forms meristic structures that have distinct symbiotic functions within the cortex of the root, extending into the soil.…”

Plant functional types and tissue stoichiometry explain nutrient transfer in common arbuscular mycorrhizal networks of temperate grasslands

“…By extension, it has been widely hypothesized that the multi-plant-fungal relationships form "common mycorrhizal networks" (CMNs) which facilitate carbon and nutrient transfer between organisms, beyond the immediate plant-fungus mutualism formed by individuals. This relationship is often simplified to the mutual exchange of carbon-based photosynthates for limiting soil nutrients that are more readily bioavailable to fungi [5], but is known to exist along a continuum from parasitic to mutualistic [6][7][8][9]. A synthesis of empirical research at macro-and micro-levels of ecological organization reveals a gap in understanding of structural and functional properties that could predict how carbon and nutrients are transferred between plants through fungi in CMNs [10].…”