BayCEER Workshop 2026

Rhizosphere microbiome structure and function in response to root exudates of Zea mays L. landraces and modern hybrids under drought

Drought and heat stress are significant contributors to global yield stagnation, with similar trends anticipated for maize in Germany. A promising strategy to address drought-induced crop yield losses involves identifying shifts in soil bacterial communities under water scarcity and harnessing specialized microbes and their functions for improved drought resilience. Beneficial plant-microbe interactions are essential for plant performance and stress resistance, yet their complexity remains poorly understood. As key mediators of plant-microbial communication, root exudates play a critical role in promoting beneficial microbiomes and facilitating adaptation to drought. Here, we propose that older landraces and modern maize hybrids may differ in their utilization of these adaptations. We investigate the influence of maize genotype on root exudation and the associated composition and activity of the rhizosphere microbiota under drought.

In this ongoing experiment, we investigate the drought response of three traditional and three modern maize varieties in two soils under three irrigation strategies. Rhizosphere microbial community composition is tracked via 16S rRNA gene metabarcoding. Initial results demonstrate an enrichment of drought-responsive taxa, including Actinobacteria, Gammaproteobacteria, and Alphaproteobacteria, particularly in dry silty loam. Contrary to our hypothesis, maize genotype was not a dominant driver of microbiome response under drought. Microbial activity in the rhizosphere is further monitored using fluorometric 4-methylumbelliferyl (MUF)-based exoenzyme assays. Understanding plant-microbe interactions under drought may help harness microbiome services for more resilient crop production.