Multi-omics reveals rhizosphere soil metabolismte-microbiota interactions in different varieties of sorghum under nutrient-deficient stress
Soil microorganisms and metabolites are the central elements of rhizosphere microenvironment, with substantial effects on nutrient acquisition, stress resilience, and yield performance in sorghum. In this study, root antioxidant enzyme activity, malondialdehyde (MDA) content, and soil properties from Jinnuo 101 and Jinnuo 102 were compared under low-nutrient condition. Changes in bacterial community structure and metabolite composition of rhizosphere and bulk soils from two sorghum cultivars were characterized using 16S rDNA high-throughput sequencing and liquid chromatography-mass spectrometry (LC-MS). Jinnuo 102 exhibits greater tolerance to low-nutrient stress conditions compared with Jinnuo 101. Under low-nutrient stress, Actinobacteria, Acidobacteria, and Bacillobacteria were significantly more abundant in sorghum rhizosphere soil than bulk soil. The Jinnuo 102 rhizosphere soil presented significantly higher Actinobacteria abundance, whereas Jinnuo 101 was significantly enriched in Cyanobacteria (P < 0.05). Metabolic pathway analysis identified the significant upregulation of “Biosynthesis of phenylpropanoids”,“Glycerophospholipid metabolism”, “Tryptophan metabolism”, and “ABC transporters”, along with the evident downregulation of “Linoleic acid metabolism” in rhizosphere soil. Biosynthesis of phenylpropanoids was significantly upregulated in rhizosphere soil of Jinnuo 102. The upregulated rhizosphere metabolites were mainly terpenoids, fatty amides or fatty acids, phenolic acids, and carbohydrates. Higher level of phenolic acids was observed in Jinnuo 102. The study reveals that tolerant sorghum enhances low-nutrient resistance by coordinately upregulating phenylpropanoid pathways and enriching beneficial rhizosphere bacteria. Theseresults provide a theoretical basis for improving sorghum tolerance to nutrientpoor conditions through regulating microbe-metabolite interactions.