Soil nutrient amendment increases the potential for inter-kingdom resource competition among foliar endophytes

Area of Science:

• Microbial ecology
• Plant-microbe interactions
• Ecosystem science

Background:

• Foliar endophytes are vital for ecosystem functions, including nutrient cycling.
• Understanding how nutrient supply affects endophyte communities is crucial but not fully explored.
• Soil nutrient enrichment can influence plant-microbe dynamics.

Purpose of the Study:

• To investigate the impact of long-term elevated nutrient supply (nitrogen, phosphorus, potassium, micronutrients - NPKμ) on foliar endophytes in *Andropogon gerardii*.
• To assess changes in taxonomic composition and carbon use phenotypes of bacterial and fungal endophytes.
• To evaluate shifts in resource competition potential among microbes within plant leaves.

Main Methods:

• Long-term field experiment with NPKμ-amended and control plots.
• Culturing and analysis of culturable bacterial and fungal foliar endophytes from *A. gerardii*.
• Characterization of endophyte carbon use profiles and taxonomic composition.

Main Results:

• Elevated NPKμ supply altered the taxonomic composition and carbon use patterns of fungal endophytes, but not bacterial endophytes.
• Fungal endophytes in nutrient-amended plots showed distinct carbon use profiles and increased specialization.
• Increased resource niche overlap between bacterial and fungal endophytes was observed with higher nutrient supply.

Conclusions:

• Soil nutrient enrichment significantly modifies fungal endophyte communities within the foliar environment.
• Changes in fungal endophyte communities may alter inter-kingdom microbial competition.
• These alterations have potential implications for large-scale ecosystem functions, such as nutrient cycling and plant productivity.