Siderophore-producing rhizobacteria improve iron and zinc accumulation in Vigna unguiculata: implications for sustainable nutrition.

Siderophores, low-molecular-weight compounds secreted by soil microorganisms, offer a sustainable approach to enhance iron (Fe) and zinc (Zn) content in crops, addressing global micronutrient malnutrition. This study examines the biofortification potential of siderophore-producing plant growth-promoting rhizobacteria (PGPR) consortia in cowpea (Vigna unguiculata), a vital legume for over 200 million people in Asia, Africa, and Latin America. Four antibiotic tagged bacterial strains, Bacillus cereus (ISM10), Pantoea agglomerans (ISM11), Pseudomonas aeruginosa (ZSM3), and Serratia marcescens (ZSM4) were combined into four consortia to leverage synergistic interactions for Fe and Zn solubilization. While previous studies have explored individual strains or limited applications, this work comprehensively investigates the synergistic potential of specific PGPR consortia (notably CSM2: P. aeruginosa + B. cereus) in both pot and field trials, showcasing substantial increases in grain Fe (88.2%) and Zn (131.9%) content, along with noticeable improvements in plant growth parameters. This holistic approach, highlighting the superior efficacy of microbial consortia over individual strains and conventional methods, offers a scalable and eco-friendly solution to "hidden hunger" and contributes to sustainable food systems.