The rhizosphere is a hotspot of plant-microbial interactions and important for plant performance. In this study we analyzed which agricultural factors (tillage, fertilization intensity, last standing field crop) shape the rhizosphere microbiota. Therefore, we setup a growth chamber experiment under controlled conditions using lettuce (Lactuca sativa L., cv. Tizian) as model plant and soils from a long-term field trial in Bernburg (Germany). After a cultivation time of ten weeks, we sampled soils, roots, the associated microbial communities, and lettuce shoots.

Our main results were:

• Tillage, last standing field crop and fertilization intensity shaped the soil and rhizosphere microbiota of lettuce, however, to different extents among the microbial groups and microhabitats studied;
• Pseudomonas was enriched in the rhizosphere of lettuce grown in soils under long-term cultivator tillage;
• Olpidium was identified as indicator for lettuce grown in extensively fertilized soils
• Best lettuce growth was recorded for soils with extensive fertilization history;
• Plants grown in soils with extensive fertilization history exhibited a higher expression of genes involved in plant stress responses which could indicate a higher tolerance or an induced physiological status when compared to intensive fertilization. This might be a reflection of root-microbial interactions;

Our study suggests that changes in agricultural management will affect soil and rhizosphere microbiota assemblage resulting in differences in plant performance. Harnessing such soil-plant-microbe interactions in agroecosystems has the potential to increase sustainability in crop production.

Read more: Babin et al. (2021):

https://doi.org/10.1093/femsec/fiab027

photo: Martin Sandmann (IGZ)