Facilitating Growth of Maize (Zea mays L.) by Biostimulants: A Perspective from the Interaction between Root Transcriptome and Rhizosphere Microbiome

The plant growth-promoting effects of biostimulants have been widely documented, while little is known about the intrinsic mechanism. In our study, a pot experiment was conducted to investigate the effects of biostimulants on maize, and the maize root transcriptome and rhizosphere microbiome were assessed. The physicochemical properties of the soil were significantly altered with various trends, and the growth and yield of maize were promoted by biostimulants. Sampling time and maize strain were the strongest factors that altered the rhizosphere microorganisms. Rhizosphere microbiota with biostimulant application exhibited high community robustness. Root transcriptome analysis suggested an altered expression profile induced by biostimulants and maize strains. An integrated correlation analysis demonstrated that phosphate and nitrate metabolism genes are tightly associated with some rhizosphere microbiota. These results implied the plant growth-promoting effects of biostimulants might act in a rhizosphere microorganism-dependent manner and help to expand the use of biostimulants in sustainable agriculture.