Host growth and defense pathways drive microbiome-mediated maize heterosis

Hybrid vigor, commonly harnessed in maize breeding to boost productivity and stress resistance, is largely attributed to genetic factors. However, recent studies suggest that environmental influences, particularly the plant microbiome, may play a pivotal role in mediating heterosis expression. This study investigates the impact of the rhizosphere microbiome on maize heterosis by exploring interkingdom interactions between plant transcriptomes and microbial communities. We identify a key link between microbial taxa and plant traits associated with heterosis, with a particular focus on root length, growth vigor and rhizoshealth. Through a combination of microbiome profiling, gene expression analysis, and functional assays, we reveal that hybrid plants may harbor a more beneficial and diverse microbiome, which could enhance traits like root development and stress tolerance. Our findings suggest that the plant microbiome, particularly through specific taxa, plays a correlative role in the manifestation of heterosis, offering new opportunities for optimizing maize breeding strategies. The study underscores the importance of the microbiome in hybrid vigor and suggests that future research into microbiome-assisted breeding could lead to more sustainable and productive maize cultivation, particularly in marginal or stressed environments.