Sultr1;2-Mediated Recruitment of Selenium-Oxidizing Bacteria Promotes Plant Selenium Uptake

Plants can shape their root microbiome to promote growth and selenium uptake. Here, we used metagenomics, 16S high-throughput sequencing, and liquid chromatography-mass spectrometry (LC-MS) metabolomics assays to investigate the role of Sultr1;2, which is the major selenium transporter gene, in recruiting microbial communities to regulate soil selenium bioavailability and plant selenium uptake. Results shows that the overexpression of Sultr1;2 in tomato significantly enriched Methylobacterium genus. The isolated strains of Methylobacterium possess multiple plant-growth-promoting functions and selenium oxidation capability and inoculation with these strains increases soil selenium availability. The upregulated metabolites of Sultr1;2-overexpressing tomato were significantly enriched in the arginine and proline metabolism pathway. The key upregulated metabolites significantly improved the growth rate and selenium-oxidizing ability of Methylobacterium strains, and the combined addition of key upregulated metabolites and synthetic microbial community significantly increased soil selenium bioavailability and plant selenium uptake. This study provides insights into leveraging plant genetic engineering to identify key functional microbial communities for sustainable selenium-rich agricultural development.