Climate change has intensified the frequency and severity of urban droughts, exposing green spaces to extreme water shortages. These events disrupt plant-microbe interactions and ecosystem functions. Extensive research has focused on the role of microbiomes in agricultural and natural ecosystems. However, understanding the dynamic regulation during drought and subsequent recovery is crucial for maintaining urban ecosystem resilience. The shift and regulatory drivers remain particularly underexplored.
Qin-Lin Chen’s group at Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, conducted microcosm experiments using Zoysia japonica, a common urban turfgrass. The team simulated four drought intensities and recovery by rehydration. Integrating omics technologies and soil enzyme stoichiometry, they analyzed alteration in microbial communities and biochemical cycling associated with carbon, nitrogen, phosphorus, and sulfur to pinpoint the drivers of urban microbial multifunctionality.
The results demonstrated that drought intensities reshaped the composition of bacteria and fungi across the rhizosphere and phyllosphere. Unexpectedly, drought enhanced microbial multifunctionality by significantly boosting 21 microbial functional potentials, including carbon fixation and denitrification. Upon rehydration, urban microbial multifunctionality largely returned to the control levels. However, legacy effects of extreme drought persisted in specific functions, notably phyllosphere organic nitrogen mineralization.
A key insight from the study was the distinct regime shift observed between drought and subsequent recovery. The analysis indicated that biotic factors, particularly rhizosphere bacteria and fungi, directly drove microbial multifunctionality during the drought phase. However, rehydration marked a transition. Soil physicochemical properties, specifically pH and ammonium nitrogen (NH 4 + -N), emerged as the main direct drivers of stabilized ecosystem functions.
The study underscores a regulatory shift. Microbes defend ecosystem functions during drought shock, while soil properties dominant the recovery stages. Effective management requires a dual focus on biology and abiotic factors. Combining drought-resilient plants with precise management of soil physicochemical conditions is essential for rapid ecosystem recovery in urban environments.
See the article:
Shift from biotic to abiotic drivers of urban microbial multifunctionality under drought and rehydration.
Science China Life Sciences