Boron-efficient varieties promote the green production of sugarbeets in boron-deficient environments by recruiting beneficial rhizosphere soil microorganisms via root exudates.

Boron (B)-efficient varieties are more capable of thriving in low-B conditions, decrease the depletion of B ore resources and reduce the likelihood of environmental contamination caused by the excessive B fertilizer inputs. However, how B-efficient beets influence soil microbiome and adapt to a B-deficient environment remain largely enigmatic. This study examines the relationship between the rhizosphere microbiome and root metabolomics using beet B-efficient (KWS1197) and B-inefficient (KWS0143) varieties. Results showed that the amount of root exudates released by B-efficient sugarbeet varieties was higher under B deficiency, and their root growth was less adversely affected by B-deficiency stress compared to B-inefficient varieties. In B-deficient environments, the relative abundance of nucleosides and nucleotides, organic 1,3-dipolar compounds, and macrolides and analogues increased in B-efficient varieties by 2.08 %, 4.86 %, and 4.47 %, respectively. In contrast, these three root exudates of B-inefficient sugarbeet varieties decreased by 3.55 %, 3.45 %, and 6.02 %. The expression of differentially expressed metabolites in B-efficient varieties increased by 46.43 %. Key differentially expressed metabolic pathways were significantly enriched, including ABC transporters, arginine, and proline metabolism biosynthesis. Notably, myristic acid significantly influenced rhizosphere soil microorganisms. Overall, B-efficient varieties mitigate B-deficiency stress by activating their antioxidant mechanisms, plant hormone signaling, and amino acid biosynthesis. These adaptations enable B-efficient sugarbeet varieties to recruit a dominant community of rhizosphere soil microorganisms (such as Gemmatimonadota, Basidiomycota, etc) thereby protecting sugarbeet from B-deficiency stress. Together, these findings enhance our understanding of plant and soil microorganisms' interaction, offering theoretical background for the use of B-efficient varieties in B-limited farming practices, and promoting sustainable agricultural practices.