Jasmonic Acid Mediates Maize (Zea mays L.) Roots Response to Soil Nitrogen Heterogeneity

A heterogeneous distribution of nutrients in the soil always affects the development of crops. In this study, we investigated the molecular mechanisms underlying the formation of phenotypic differences between the high- and low-nitrogen side roots of maize in response to soil nitrogen heterogeneity using a multiomics approach. The transcriptome data show that 1147 differentially expressed genes (DEGs) were identified on the high- and low-nitrogen sides roots, with 791 down-regulated and 356 up-regulated expressions, respectively, which were concentrated mainly in the plant hormone signal transduction pathway and the plant mitogen-activated protein kinase(MAPK)signaling pathway. Metabolomics show that a total of 77 differentially accumulated metabolites (DAMs) were detected in the high- and low-nitrogen side roots, with 13 up-regulated and 64 dow-nregulated, respectively, and the analysis of the KEGG pathway showed that DAMs were mainly enriched in flavone and flavonol biosynthesis and the biosynthesis of secondary metabolites. The combined analysis shows that the jasmonic acid (JA) signaling pathway in plant hormone signal transduction was significantly different between the two sides of the roots. Jasmonoyl-L-isoleucine (JA-Ile) may be a key factor in the response of maize roots to soil nitrogen heterogeneity, and the transcription factors JAZ and MYC2 regulate this pathway. In summary, transcriptomics and metabolomics have improved our understanding of how nitrogen application patterns affect root development in agroecosystems and provide a scientific basis for precision fertilization for high crop productivity.