Foliar application of indole-3-acetic acid drives changes of soil fungal communities in endosphere and rhizosphere of Eucommia ulmoides

Aims: Eucommia ulmoides is a valuable tree species endemic to China. However, the limited scale and low prevalence of quality seed resources, coupled with their slow growth and low utilization rate, continue to result in a scenario where supply falls short of demand. Growth hormone plays an important role in the growth and development of plants, notably enhancing the rooting rate of E. ulmoides . Methods: In this study, based on high-throughput sequencing technology and controlled pot experiments, to assess the influence on the endosphere and rhizosphere fungal communities, the impact of varying concentrations of indole-3-acetic acid (IAA) on the foliar application of E. ulmoides were explored. Results: The results revealed that the application of IAA significantly altered the composition, diversity and functionality of the fungal communities within the endosphereand rhizosphere of E. ulmoides . The most pronounced effects were observed at an IAA concentration of 1000 µM, with a more substantial impact on the rhizosphere fungi compared to those in the endosphere fungi. Futhermore, the application of IAA significantly increased the abundance of beneficial fungi in the endosphere, which are crucial for the growth and health of E. ulmoides . Conclusions: This study revealed that the foliar spray of IAA could significantly drived the change of fungal community composition in the rhizosphere and endosphere of E. ulmoides , and increased the beneficial functional microbiota. This study offers novel insights into efficient and sustainable agricultural practices from a microbiological perspective.