Magnetotactic bacteria as biostimulants for enhancing the growth and yield of tomato and paddy under abiotic stress

Fuente: PubMed "industrial biotechnology"
Front Microbiol. 2026 Jun 26;17:1848546. doi: 10.3389/fmicb.2026.1848546. eCollection 2026.ABSTRACTNutrient imbalances, soil salinity, and shrinking arable land threaten global food security, driving demand for sustainable biofertilizer alternatives to chemical inputs. Aquatic ecosystem-derived biofertilizers such as Magnetospirillum gryphiswaldense (MSR-1) are promising sustainable substitutes and show strong agricultural potential due to their stress tolerance, adaptability, and plant growth-promoting traits. This study investigated the ability of MSR-1 to enhance the growth and productivity of tomato and paddy under normal, iron-deficient, and saline conditions. MSR-1 was cultured in modified Magnetospirillum Growth Medium (MSGM) under microaerophilic conditions, with SEM confirming its spiral gram-negative morphology and successful, non-destructive colonization on tomato and paddy roots and leaves. Moreover, HR-LCMS profiling of root exudates identified chemoattractant compounds such as quinic acid, tryptophan, quercetin, glucosinolates, and strigolactones, promoting bacterial attachment. Further, Magnetospirillum liquid biofertilizer (MLB) was formulated from MSR-1 cultures (1.5 × 108 cells/mL) and applied at 20-100% concentrations (25 mL/pot). Among the treatments, 20% MLB gave the best results under normal conditions, whereas 60% MLB was more effective under iron-deficient and saline stress conditions. In tomato, 20% MLB increased shoot length (73.5 cm), chlorophyll content (4.5 mg/g), and fruit yield (1066.95 g/plant). Under stress, 60% MLB improved fruit yield (760-800 g/plant) and boosted antioxidant enzymes (SOD 75 U/mg; CAT 15.5 U/mg). In paddy, 20% MLB enhanced shoot and root length (66.0 and 15.13 cm), while 60% MLB under stress increased growth, carbohydrates, proteins, amino acids, phenols, and antioxidant enzymes (SOD/CAT 49.63/19.83 U/mg). Overall, MSR-1 offers a sustainable, effective biofertilizer option for managing soil salinity and iron deficiency.PMID:42434551 | PMC:PMC13350338 | DOI:10.3389/fmicb.2026.1848546