Shifts of Leaf Litter-Induced Plant-Soil Feedback from Negative to Positive Driven by Ectomycorrhizal Symbiosis between Quercus ilex and Pisolithus arrhizus

Interactive effects of rhizospheric soil microbes and litter on the growth of the invasive hyperaccumulator Bidens pilosa in cadmium-contaminated soil

Both rhizospheric soil microbes and shoot litter input can have profound effects on plant performance; however, their interactive effects on plants in Cd-contaminated soils remain poorly understood. We grew an invasive hyperaccumulator, Bidens pilosa, in sterilized and unsterilized rhizosphere soil without litter or with a low (0.2%, dry weight ratio) or a high amount (1%) of litter from B. pilosa in soil with low (5 mg kg-1) or high (10 mg kg-1) concentrations of Cd. The total, shoot, and root biomass of B. pilosa increased significantly with litter addition, by an average of 27%, 28%, and 20%, respectively. The biomass of B. pilosa was significantly lower in unsterilized rhizosphere soil than in sterilized rhizosphere soil, decreasing by 19% for total, 18% for shoot, and 24% for root, respectively. Furthermore, the effects of different litter amounts (0.2% vs. 1%) on biomass did not vary in sterilized rhizosphere soils but significantly varied in unsterilized rhizosphere soils, showing that the biomass was significantly lower with 1% litter addition than with 0.2% litter addition in unsterilized rhizosphere soils, decreasing by 28% for total, 29% for shoot, and 21% for root, respectively. Tissue Cd concentrations were significantly higher in highly Cd-contaminated soils (+75% for shoot and +51% for root) than in low Cd-contaminated soils; however, higher tissue Cd concentrations did not cause a significant decrease in the biomass of B. pilosa. Soil fungal communities, particularly the dominant phyla, Ascomycota and Basidiomycota, play crucial roles in modulating the effects of rhizosphere soil microbes and litter on the growth of B. pilosa. Our results suggest that rhizosphere soil microbes and litter interact and affect the growth of B. pilosa: litter addition promoted growth by increasing the abundance of saprotrophs (especially Basidiomycota) and decreasing Cd accumulation in plant tissues, and rhizosphere soil inhibition was associated with a decreased abundance of Basidiomycota. Our findings highlight the importance of the interactive effects of rhizospheric soil microbes and litter on plant growth in Cd-contaminated soils.

Age-Related Conservation in Plant-Soil Feedback Accompanied by Ectomycorrhizal Domination in Temperate Forests in Northeast China

This study investigates the effects of forest aging on ectomycorrhizal (EcM) fungal community and foraging behavior and their interactions with plant-soil attributes. We explored EcM fungal communities and hyphal exploration types via rDNA sequencing and investigated their associations with plant-soil traits by comparing younger (~120 years) and older (~250 years) temperate forest stands in Northeast China. The results revealed increases in the EcM fungal richness and abundance with forest aging, paralleled by plant-soil feedback shifting from explorative to conservative nutrient use strategies. In the younger stands, Tomentella species were prevalent and showed positive correlations with nutrient availability in both the soil and leaves, alongside rapid increases in woody productivity. However, the older stands were marked by the dominance of the genera Inocybe, Hymenogaster, and Otidea which were significantly and positively correlated with soil nutrient contents and plant structural attributes such as the community-weighted mean height and standing biomass. Notably, the ratios of longer-to-shorter distance EcM fungal exploration types tended to decrease along with forest aging. Our findings underscore the integral role of EcM fungi in the aging processes of temperate forests, highlighting the EcM symbiont-mediated mechanisms adapting to nutrient scarcity and promoting sustainability in plant-soil consortia.

Checklist of Macrofungi Associated with Nine Different Habitats of Taburno-Camposauro Massif in Campania, Southern Italy

The checklist serves as an informative method for evaluating the diversity, geography, and ecology of established and reproducing macrofungi. Additionally, considering macrofungi as bioindicator species, their census should be incorporated into efforts to monitor the state of health of ecosystems and directly applied to conservation policies. Between 2019 and 2023, a census of macrofungal species was conducted in Taburno-Camposauro Regional Park (Campania, Italy) across nine distinct habitats. A total of 453 fungal taxa were identified, including several new records for the Campania region. The fungal diversity exhibited significant variations based on the dominant plant species in each habitat. Fagacean tree species and Carpinus spp. shared similar fungal communities. Equally, coniferous tree species displayed a comparable fungal composition. In Abies alba and mixed broad-leaved forests, low levels of ectomycorrhizal taxa were observed alongside a concurrent increase in saprotrophs, indicating a disturbed habitat and a reduction in the Gadgil effect. Notably, lower fungal diversity was documented in the grassland habitat, suggesting the potential implications of wildlife imbalance and excessive grazing. The provided checklist constitutes a valuable resource for local management authorities, providing insights to formulate specific management policies.