Lettuce fortification through vitamin B₁₂-producing bacteria - proof of concept study

Area of Science:

• Microbiology
• Nutritional Science
• Plant Biotechnology

Background:

• Vitamin B12 (cobalamin) is essential for human and animal health but is primarily synthesized by microorganisms.
• Dietary intake is the sole source for humans, predominantly from animal products, leading to deficiency risks in vegetarian, vegan, and poorly-nourished populations.
• Endophytic bacteria residing within plant tissues offer a potential avenue for biofortification.

Purpose of the Study:

• To identify endophytic bacterial strains capable of synthesizing vitamin B12.
• To evaluate the potential of these bacteria to enrich edible plants with vitamin B12.
• To explore a sustainable solution for vitamin B12 deficiency in specific dietary groups.

Main Methods:

• In silico genome analysis of 66 bacterial strains using RAST server and MetaCyc database to identify vitamin B12 metabolic pathways.
• Confirmation of vitamin B12 production using High-Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD).
• In planta efficacy testing of selected strains in lettuce under sterile conditions, with and without cobalt chloride supplementation.

Main Results:

• Eleven bacterial strains demonstrated detectable vitamin B12 production under laboratory conditions.
• Methylobacterium sp. strain P1-11 successfully produced vitamin B12 in lettuce (in planta).
• Cobalt chloride supplementation significantly enhanced vitamin B12 production in planta by Methylobacterium sp. strain P1-11.

Conclusions:

• This study demonstrates, for the first time, the successful use of a bacterial endophyte for in planta vitamin B12 production.
• Bacterial endophytes hold significant potential for enhancing the nutritional value of plant-based foods.
• This approach offers a promising strategy for biofortification and addressing vitamin B12 deficiency through plant-based food sources.