Microbiome-Safe Calcium Carbonate Nanocarriers Enhance Drought Tolerance in Iraqi Wheat

Especially in dry parts of the Middle East like Iraq, food security is seriously threatened by rising problems of climate volatility and severe water shortage. Under abiotic stress, calcium (Ca) is a necessary macronutrient that is vital for controlling signal transduction pathways and preserving cell wall integrity. Low solubility and variable bioavailability, however, restrict the traditional uses of bulk Calcium sources.This research looks at how well Calcium Carbonate nanoparticles (CaCO3 NPs) coated with the amphiphilic triblock copolymer Pluronic F68 (F68) can help the Iraqi wheat variety Triticum aestivum L. cv. Ibaa 99 receive more of its nutrients. To guarantee microbiome safety, the concurrent interaction of this nanocarrier system with a local helpful rhizobacterium, Pseudomonas sp. (isolate PK 1), was tested. The University of Karbala's laboratory facilities were the sole location for the study's Stable F68- CaCO3 composites were shown by physicochemical analysis to have been successfully produced. Biological studies showed that F68-CaCO3 NPs moved to shoot tissues and stuck to root surfaces, especially in leaf trichomes. Soil application of F68-CaCO3 NPs under drought stress circumstances boosted shoot dry weight by 13.6% (p <0.01) and sustained greater Relative Water Content (84.7%) than controls. Along with these advances, proline buildup decreased, indicating that improved Calcium bioavailability and membrane stabilisation helped to reduce osmotic stress. Importantly, unlike the osmolyte glycine betaine (GB), the F68-CaCO3 system showed no toxicity to Pseudomonas sp. PK-1 and was not digested by the bacteria. Under the experimental settings of this research, this supports the hypothesis that F68-CaCO3 is a microbiome-friendly nanocarrier platform. These results indicate that biocompatible Calcium-based nanocarriers provide a sustainable and effective way to provide vital nutrients to Iraqi crops while also keeping the functional integrity of the helpful root microbiome.