Effects of experimental warming on soil microbial influence on plant growth in an alpine meadow of the Qinghai-Tibetan Plateau

With ongoing climate warming, microbial diversity and community composition are experiencing profound shifts that impact their functional roles in ecosystems. However, the effects of these shifts on plant growth, particularly in alpine ecosystems, remain poorly understood. In this study, we used an in situ mesocosm to examine the net effects of soil biota derived from long-term warming-treated soils on plant growth (Elymus nutans and Poa annus) on the Qinghai-Tibetan Plateau. Plant total biomass was compared between sterile soils inoculated with either live or sterilized inoculum under control and warming condition respectively. Soil microbial communities were also analyzed to explore their associations with plant growth. Our results show that soil microbial communities consistently suppressed plant growth, and long-term warming exacerbated these negative effects. This response exhibited species-specific patterns, with a significant effect observed for P. annua, but not for E. nutans. Moreover, these functional shifts in microbial effects were linked to changes in the abundance of specific microbial taxa, such as Spizellomyces and Flavobacterium. Overall, this study provides new insights into how warming-induced changes in soil microbial communities influence plant growth, emphasizing the critical role of microbial associations in shaping species-specific plant responses to climate change.