Table 2.
Studies of micronutrient biofortification using beneficial soil microorganisms.
| Targeted Plant | Evaluation | Improvement in Nutritional Value | Contribution to Crop Productivity | Reference |
|---|---|---|---|---|
| Maize (Zea mays L.) | Seed priming with Alcaligenes sp., Bacillus sp., Pseudomonas sp., and Bacillus sp. | Zn contents increased by 33.0%, 15.3%, 49.1%, and 15.6% in roots, grain, stem, and cob-pith. | Treatments improved cob length and diameter by 42% and 16.75%, respectively, and increased 100-grain weight by 18.4%. | [109] |
| Wheat (Triticum aestivum L. cv. Zhoumai) | Seed soaking and soil spraying with Bacillus altitudinis WR10 under field conditions. | Total N and K contents were enhanced by more than 50%. Fe content rose between 29.94% and 18.67%. Fe was accumulated mainly in the embryo and endosperm. | Inoculum increased kernels per spike (24.67–16.44%) and total chlorophyll content (42.07–22.85%). | [110] |
| Maize (Zea mays L.) | Field trial with Bacillus sp. AZ6. | Treatments improved grain Zn content (46%), shoot Zn content (52%), crude protein (12.8%), fiber (2.8%), carotenoids (17%), and chlorophyll content (57%), and decreased phytate (73%). | Biofertilizer increased plant height (10%-53%), dry shoot-biomass (46%), photosynthetic rate (47%), transpiration rate (42%), and stomatal conductance (45%). | [119] |
| Mungbean (Vigna radiata L.) | Pot study using Pantoea dispersa MPJ9 and Pseudomonas putida MPJ6. | Rhizobacteria showed iron-chelating activity (89.9–85.3%) and improved iron (3.4-fold), protein (2.5-fold), and carbohydrate content (1.5-fold). |
Improved the maximum seed germination percentage (93.3%), shoot and root length, and fruit weight. | [111] |
| Coriander (Coriandrum sativum L.) | In vitro and greenhouse experiments with Bacillus halotolerans. | Increases in carbon (1.48%), calcium (1.23%), iron (179%), magnesium (3.30%), nitrogen (11.9%), and phosphorus (38.2%) contents. | Enhancement of stem length by up to 5.9%, shoot dry weights (15.8%), and chlorophyll content (34.1%). | [113] |
| Lettuce (Lactuca sativa L.) | Greenhouse test using Pseudomonas sp. and Azospirillum brasilense strains and nitrogen fertilizer doses (30–120 kg/ha). | Increases in carotenoid content (47%), ascorbic acid (42%), total phenolics (17%), and total chlorophyll (20%). | Bacteria improved plant height (15%), lettuce head fresh weight (48%), and root collar diameter (70%). | [112] |
| Cabbage (Brassica oleracea var. capitata L.) | Pot study with Azotobacter and phosphorus and potassium solubilizing bacteria. | Treatments increased vitamin C content by 17% and total soluble solids (TSS) of cabbage heads by 3%. | Improved the cabbage head’s polar diameter (8%) and equatorial diameter (4%). | [120] |
| Tomato (Solanum lycopersicum L. cv. Rio Grande) | Consortia of Bacillus species, Azotobacter chroococcum, and Pseudomonas megaterium. | Bacteria improved lycopene (52.8%) and total carotenoids (25%) contents, TSS, pectin methylesterase (PME), polygalacturonase (PG), and antioxidant (31.25%) activities in tomato fruit. | Increases in dry weight (39%), photosynthetic rate (9.9%), fruit weight per plant (26.78–30.70%), and yield (51.94%). | [121] |