Common mycorrhizal networks amplify competition by preferential mineral nutrient allocation to large host plants.

Arbuscular mycorrhizal (AM) fungi interconnect plants in common mycorrhizal networks (CMNs) which can amplify competition among neighbors. Amplified competition might result from the fungi supplying mineral nutrients preferentially to hosts that abundantly provide fixed carbon, as suggested by research with organ-cultured roots. We examined whether CMNs supplied (15) N preferentially to large, nonshaded, whole plants. We conducted an intraspecific target-neighbor pot experiment with Andropogon gerardii and several AM fungi in intact, severed or prevented CMNs. Neighbors were supplied (15) N, and half of the target plants were shaded. Intact CMNs increased target dry weight (DW), intensified competition and increased size inequality. Shading decreased target weight, but shaded plants in intact CMNs had mycorrhizal colonization similar to that of sunlit plants. AM fungi in intact CMNs acquired (15) N from the substrate of neighbors and preferentially allocated it to sunlit, large, target plants. Sunlit, intact CMN, target plants acquired as much as 27% of their nitrogen from the vicinity of their neighbors, but shaded targets did not. These results suggest that AM fungi in CMNs preferentially provide mineral nutrients to those conspecific host individuals best able to provide them with fixed carbon or representing the strongest sinks, thereby potentially amplifying asymmetric competition below ground.

Common mycorrhizal network: the predominant socialist and capitalist responses of possible plant-plant and plant-microbe interactions for sustainable agriculture.

Plants engage in a variety of interactions, including sharing nutrients through common mycorrhizal networks (CMNs), which are facilitated by arbuscular mycorrhizal fungi (AMF). These networks can promote the establishment, growth, and distribution of limited nutrients that are important for plant growth, which in turn benefits the entire network of plants. Interactions between plants and microbes in the rhizosphere are complex and can either be socialist or capitalist in nature, and the knowledge of these interactions is equally important for the progress of sustainable agricultural practice. In the socialist network, resources are distributed more evenly, providing benefits for all connected plants, such as symbiosis. For example, direct or indirect transfer of nutrients to plants, direct stimulation of growth through phytohormones, antagonism toward pathogenic microorganisms, and mitigation of stresses. For the capitalist network, AMF would be privately controlled for the profit of certain groups of plants, hence increasing competition between connected plants. Such plant interactions invading by microbes act as saprophytic and cause necrotrophy in the colonizing plants. In the first case, an excess of the nutritional resources may be donated to the receiver plants by direct transfer. In the second case, an unequal distribution of resources occurs, which certainly favor individual groups and increases competition between interactions. This largely depends on which of these responses is predominant ("socialist" or "capitalist") at the moment plants are connected. Therefore, some plant species might benefit from CMNs more than others, depending on the fungal species and plant species involved in the association. Nevertheless, benefits and disadvantages from the interactions between the connected plants are hard to distinguish in nature once most of the plants are colonized simultaneously by multiple fungal species, each with its own cost-benefits. Classifying plant-microbe interactions based on their habitat specificity, such as their presence on leaf surfaces (phyllospheric), within plant tissues (endophytic), on root surfaces (rhizospheric), or as surface-dwelling organisms (epiphytic), helps to highlight the dense and intricate connections between plants and microbes that occur both above and below ground. In these complex relationships, microbes often engage in mutualistic interactions where both parties derive mutual benefits, exemplifying the socialistic or capitalistic nature of these interactions. This review discusses the ubiquity, functioning, and management interventions of different types of plant-plant and plant-microbe interactions in CMNs, and how they promote plant growth and address environmental challenges for sustainable agriculture.

Parasitic plants regulate C and N distribution among common mycorrhizal networks linking host and neighboring plants.

Common mycorrhizal networks (CMNs) can link multiple plants and distribute nutrients among them. However, how parasitic plants regulate the carbon and nutrient exchange between CMNs and the linked plants is unknown. Thus, we conducted a container experiment with two Trifolium pratense grown in two plastic cores and connected only by CMNs using a 25-µm nylon fabric in each container. Host T. pratense was parasitized or not parasitized by Cuscuta gronovii. CMNs were left intact or broken by rotating the cores with the host or neighboring T. pratense. The dual 15N and 13C labeling method was used to evaluate the N distributed by CMNs to the host and neighboring T. pratense and the recently fixed C from the host and neighboring T. pratense to CMNs. The results showed that CMNs distributed more 15N to unparasitized neighboring T. pratense than the parasitized host T. pratense. Moreover, the unparasitized neighboring T. pratense provides more recently fixed C to CMNs than the parasitized host T. pratense. These results revealed that the parasite regulated C and nutrient exchange between CMNs and the linked plants following the reciprocal rewards rule. Moreover, this study highlights the importance of parasitic plants in the regulation of mutualistic interactions in ecological webs.

Genetically Engineered-Cell-Membrane Nanovesicles for Cancer Immunotherapy.

The advent of immunotherapy has marked a new era in cancer treatment, offering significant clinical benefits. Cell membrane as drug delivery materials has played a crucial role in enhancing cancer therapy because of their inherent biocompatibility and negligible immunogenicity. Different cell membranes are prepared into cell membrane nanovesicles (CMNs), but CMNs have limitations such as inefficient targeting ability, low efficacy, and unpredictable side effects. Genetic engineering has deepened the critical role of CMNs in cancer immunotherapy, enabling genetically engineered-CMN (GCMN)-based therapeutics. To date, CMNs that are surface modified by various functional proteins have been developed through genetic engineering. Herein, a brief overview of surface engineering strategies for CMNs and the features of various membrane sources is discussed, followed by a description of GCMN preparation methods. The application of GCMNs in cancer immunotherapy directed at different immune targets is addressed as are the challenges and prospects of GCMNs in clinical translation.

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Plant-plant interactions is one of the key field in ecology, which is important for the efficient nutrient utilization, productivity improvement, and plant community assembly. Arbuscular mycorrhizal fungi are important plant mutualistic microorganisms that connect plant roots to form common mycelial networks (CMNs), which play major roles in transferring nutrients and water and regu-lating plant community dynamics. Recent studies demonstrated that these CMNs could act as conduits for transmitting disease and aphid-induced signals among plants, and activating chemical defence in uninfested neighboring plants. In this review, we introduced recent research advances on the contribution of CMNs on plant interaction, the main factors that influences the functions of CMNs, and the role of CMNs transfer and redistribute nutrients and water among plant. In addition, the mechanism underlying underground chemical signal communication, seedling establishment and plants community assembly were summarized. Finally, we proposed challenges facing CMNs in plant-plant interactions and the practical problems. It would provide reference for further understanding the ecological functions of CMNs in plant-plant interactions.

Little Cross-Feeding of the Mycorrhizal Networks Shared Between C3-Panicum bisulcatum and C4-Panicum maximum Under Different Temperature Regimes.

Common mycorrhizal networks (CMNs) formed by arbuscular mycorrhizal fungi (AMF) interconnect plants of the same and/or different species, redistributing nutrients and draining carbon (C) from the different plant partners at different rates. Here, we conducted a plant co-existence (intercropping) experiment testing the role of AMF in resource sharing and exploitation by simplified plant communities composed of two congeneric grass species (Panicum spp.) with different photosynthetic metabolism types (C3 or C4). The grasses had spatially separated rooting zones, conjoined through a root-free (but AMF-accessible) zone added with 15N-labeled plant (clover) residues. The plants were grown under two different temperature regimes: high temperature (36/32°C day/night) or ambient temperature (25/21°C day/night) applied over 49 days after an initial period of 26 days at ambient temperature. We made use of the distinct C-isotopic composition of the two plant species sharing the same CMN (composed of a synthetic AMF community of five fungal genera) to estimate if the CMN was or was not fed preferentially under the specific environmental conditions by one or the other plant species. Using the C-isotopic composition of AMF-specific fatty acid (C16:1ω5) in roots and in the potting substrate harboring the extraradical AMF hyphae, we found that the C3-Panicum continued feeding the CMN at both temperatures with a significant and invariable share of C resources. This was surprising because the growth of the C3 plants was more susceptible to high temperature than that of the C4 plants and the C3-Panicum alone suppressed abundance of the AMF (particularly Funneliformis sp.) in its roots due to the elevated temperature. Moreover, elevated temperature induced a shift in competition for nitrogen between the two plant species in favor of the C4-Panicum, as demonstrated by significantly lower 15N yields of the C3-Panicum but higher 15N yields of the C4-Panicum at elevated as compared to ambient temperature. Although the development of CMN (particularly of the dominant Rhizophagus and Funneliformis spp.) was somewhat reduced under high temperature, plant P uptake benefits due to AMF inoculation remained well visible under both temperature regimes, though without imminent impact on plant biomass production that actually decreased due to inoculation with AMF.

Reciprocal N (15 NH4 + or 15 NO3 - ) transfer between nonN2 -fixing Eucalyptus maculata and N2 -fixing Casuarina cunninghamiana linked by the ectomycorrhizal fungus Pisolithus sp.

• Two-way N transfers mediated by Pisolithus sp. were examined by excluding root contact and supplying 15 NH4 + or 15 NO3 - to 6-month-old Eucalyptus maculata or Casuarina cunninghamiana grown in two-chambered-pots separated by 37 m screens. • Mycorrhizal colonization was 35% in Eucalyptus and 66% in Casuarina (c. 29% N2 -fixation). Using an environmental scanning electron microscope, living hyphae were observed to interconnect Eucalyptus and Casuarina. Biomass and N accumulation was greatest in nodulated mycorrhizal Casuarina/mycorrhizal Eucalyptus pairs, less in nonnodulated mycorrhizal Casuarina/mycorrhizal Eucalyptus pairs, and least in nonnodulated nonmycorrhizal Casuarina/nonmycorrhizal Eucalyptus pairs. • In nonnodulated mycorrhizal pairs, N transfers to Eucalyptus or to Casuarina were similar (2.4-4.1 mg per plant in either direction) and were 2.6-4.0 times greater than in nonnodulated nonmycorrhizal pairs. In nodulated mycorrhizal pairs, N transfers were greater to Eucalyptus (5-7 times) and to Casuarina (12-18 times) than in nonnodulated mycorrhizal pairs. Net transfer to Eucalyptus or to Casuarina was low in both nonnodulated nonmycorrhizal (< 0.7 mg per plant) and nonnodulated mycorrhizal pairs (< 1.1 mg per plant). In nodulated mycorrhizal pairs, net transfer to Casuarina was 26.0 mg per plant. • The amount and direction of two-way mycorrhiza-mediated N transfer was increased by the presence of Pisolithus sp. and Frankia, resulting in a net N transfer from low-N-demanding Eucalyptus to high-N-demanding Casuarina.