Maize drought stress rhizosphere (GEMMA)
Climate change is bringing new limitations and challenges to agriculture, especially as the global policies try to reduce the inputs needed for crop production. In this scenario, harnessing the natural resources available to find strategies to mitigate stress while maintaining sustainability is an important goal for agriculture. Landraces are potential sources of interesting genetic traits related to stress tolerance and these traits can be related not only to their own genome but also to their ability to interact with microbes more efficiently than most elite genotypes. In this study, we investigated the rhizosphere microbiota of four different maize landraces from Lombardy region (Northern Italy), grown under controlled conditions in soil from four different locations in Lombardy, initially under well-watered conditions and then under water scarcity. Moreover, growth and photosynthetic parameters were monitored to correlate the microbiota characteristics with the stress level of the plants. The results highlight a strong influence of the specific soil/genotype combination on the rhizosphere microbiota in well-watered conditions, generally accompanied by a selective recruitment of Bacillota bacteria. In contrast, water scarcity brings about a homogenization of the rhizosphere bacterial communities that do not differ significantly from bulk soil in most cases. The combinations of soils and landraces that showed best tolerance to the water scarcity conditions were also those characterized by peculiar rhizosphere microbiota compositions, reinforcing the idea that some landraces can be more effective in mitigating stress by interacting with specific microorganisms.