Global climate change stressors are altering soil function and reducing crop yields, yet the role of soil microbial legacies in shaping plant stress responses remains poorly understood. Here, we tested how long-term farming (organic vs conventional) and climate (ambient vs future) legacies of soil microbiomes influence wheat performance under drought. Soil samples were collected from long-term experimental plots at the Global Change Experimental Facility (GCEF, Germany) and used to extract microbial communities. These microbial extracts were then used to inoculate sterilized potting soil in which two wheat cultivars, drought-sensitive Nordkap and drought-tolerant SU Fiete, were grown under controlled greenhouse drought. Microbial inoculation enhanced germination relative to non-inoculated controls, with conventionally managed and ambient-climate microbiomes yielding the highest germination percentage. For plant dry weight content (DWC), inoculation effects under drought were cultivar-specific, where Nordkap showed the strongest DWC increase when paired with future-climate microbiomes. However, in SU Fiete, drought combined with future-climate inocula led to the lowest DWC. The rhizosphere of plants inoculated with organic-derived microbes harbored more unique ASVs (442 bacterial and 70 fungal) than those receiving conventional-derived microbiomes (381 bacterial and 48 fungal). We further showed that rhizosphere bacterial communities were influenced by complex interactions between microbial legacy (farming and climate), cultivar, and water stress, while fungal communities tracked only farming legacy. Together, these results demonstrate that soil microbiomes retain the imprint of past farming management and climate conditions, and that these legacies can either buffer or exacerbate plant stress responses in a cultivar-dependent manner. • Soil microbiome history shaped wheat performance and rhizosphere community structure under drought. • Conventional–ambient microbiomes enhanced wheat germination . • Farming history best explained bacterial and fungal rhizosphere community shifts. • Organic-derived microbiomes increased fungal diversity and unique rhizosphere taxa.
Sharma et al. (2026) studied this question.