Soil phosphorus form affects the advantages that arbuscular mycorrhizal fungi confer on the invasive plant species, Solidago canadensis, over its congener

Soil bacterial community could be affected by Amaranthus retroflexus L

Invasive plants can disrupt the growth performance of native plants by releasing allelochemicals affecting on litter decomposition. Furthermore, these invaders can establish a plant-soil feedback loop with soil microorganisms, which promotes their continued successful invasion primarily through decomposition process. Consequently, it is of the utmost importance to conduct research that analyzes the impacts of invasive plants' allelopathy on their interaction with soil microorganisms. This study aims to investigate the effects of Amaranthus retroflexus L., an invasive Amaranthaceae plant's allelopathy, on its interaction with soil bacterial communities, compared to the native plant A. tricolor L., and also the impacts of the allelopathy of Amaranthus retroflexus on soil enzyme activities. The research was conducted via an indoor planting experiment in which a gradient of Amaranthus retroflexus leaf litter was added. In particular, Amaranthus retroflexus leaf litter resulted in an increase in pH, electrical conductivity, total nitrogen, and neutral protease activity in soil under certain treatments. The amount of Amaranthus retroflexus leaf litter and the form of incubation condition may be the primary determinants of the composition of bacterial communities in soil and the number of functional gene pathways of soil bacteria involved in the decomposition process (especially the decomposition of carbon-containing substances), rather than the alpha diversity of soil bacteria. Consequently, Amaranthus retroflexus may predominantly modify the composition of bacterial communities in soil and the number of functional gene pathways of soil bacteria involved in the decomposition process, rather than the alpha diversity of soil bacteria, to facilitate its subsequent invasion.

Spartina alterniflora modifies the native arbuscular mycorrhizal fungal community in coastal ecosystem

The effect of invasive plants is mediated by their interactions with microbial communities. However, it is still uncertain how Spartina alterniflora impacts the arbuscular mycorrhizal fungi (AMF) community within the native rhizosphere what the resulting AMF differences are associated with. Here, we investigated what kind of AMF communities are formed in the roots of S. alterniflora to distinguish it from native plants such as Suaeda salsa, Phragmites australis, and Tamarix chinensis by analyzing the AMF communities and the associations with selected environmental factors. The dynamics of AM fungal communities are linked to plant-soil systems. The AMF communities of S. alterniflora and native vegetation demonstrated notable differences in composition, diversity, and symbiotic networks. Significantly higher ω, Ec, AN, AP, and AK were observed in S. alterniflora-invaded soils. Although plant rhizosphere AMF responded to soil environmental factors, AN and AP were highly explanatory environmental factors driving AMF community characteristics during S. alterniflora expansion, while increased soil P and N availability may be involved in shaping AMF community characteristics in S. alterniflora. Our findings can provide complementary evidence-based solutions for defending against invasive plants and mitigating their impacts, as well as protecting coastal ecosystems.

Soil polluted system shapes endophytic fungi communities associated with Arundo donax: a field experiment

With the expansion of the mining industry, environmental pollution from microelements (MP) and red mud (RM) has become a pressing issue. While bioremediation offers a cost-effective and sustainable solution, plant growth in these polluted environments remains difficult. Arundo donax is one of the few plants capable of surviving in RM-affected soils. To identify endophytic fungi that support A. donax in different contaminated environments and to inform future research combining mycorrhizal techniques with hyperaccumulator plants, we conducted a field experiment. The study compared endophytic fungal communities in A. donax grown in uncontaminated, MP soils contaminated with cadmium (Cd), arsenic (As), and lead (Pb), and RM-contaminated soils. Our findings showed that soil nutrient profiles differed by contamination type, with Cd concentrations in MP soils exceeding national pollution standards (GB 15168-2018) and RM soils characterized by high aluminum (Al), iron (Fe), and alkalinity. There were significant differences in the endophytic fungal community structures across the three soil types (p < 0.001). Co-occurrence network analysis revealed that endophytic fungi in MP soils exhibited competitive niche dynamics, whereas fungi in RM soils tended to share niches. Notably, Pleosporales sp., which accounted for 18% of the relative abundance in RM soils, was identified as a dominant and beneficial endophyte, making it a promising candidate for future bioremediation efforts. This study provides valuable insights into the role of endophytic fungi in phytoremediation and highlights their potential as resources for improving plant-microbe interactions in contaminated environments.

Influence of plant species, mycorrhizal inoculant, and soil phosphorus level on arbuscular mycorrhizal communities in onion and carrot roots

Arbuscular mycorrhizal fungi (AMF) are ancient and ecologically important symbionts that colonize plant roots. These symbionts assist in the uptake of water and nutrients, particularly phosphorus, from the soil. This important role has led to the development of AMF inoculants for use as biofertilizers in agriculture. Commercial mycorrhizal inoculants are increasingly popular to produce onion and carrot, but their specific effects on native mycorrhizal communities under field conditions are not known. Furthermore, adequate availability of nutrients in soils, specifically phosphorus, can reduce the diversity and abundance of AMF communities in the roots. The type of crop grown can also influence the composition of AMF communities colonizing the plant roots. This study aimed to investigate how AMF inoculants, soil phosphorus levels, and plant species influence the diversity of AMF communities that colonize the roots of onion and carrot plants. Field trials were conducted on high organic matter (muck) soil in the Holland Marsh, Ontario, Canada. The treatments included AMF-coated seeds (three to five propagules of Rhizophagus irregularis per seed) and non-treated onion and carrot seeds grown in soil with low (~46 ppm) and high (~78 ppm) phosphorus levels. The mycorrhizal communities colonizing the onion and carrot roots were identified by Illumina sequencing. Five genera, Diversispora, Claroideoglomus, Funneliformis, Rhizophagus, and Glomus, were identified in roots of both plant species. AMF communities colonizing carrot roots were more diverse and richer than those colonizing onion roots. Diversispora and Funneliformis had a 1.3-fold and 2.9-fold greater abundance, respectively, in onion roots compared to carrots. Claroideoglomus was 1.4-fold more abundant in carrot roots than in onions. Inoculation with R. irregularis increased the abundance and richness of Rhizophagus in AMF communities of onion roots but not in carrot roots. The soil phosphorus level had no effect on the richness and diversity of AMF in the roots of either crop. In summary, AMF inoculant and soil phosphorus levels influenced the composition of AMF communities colonizing the roots of onion and carrot plants, but the effects varied between plant species.