Pseudomonas-aided zinc application improves the productivity and biofortification of bread wheat

Abstract

Zinc (Zn) deficiency reduces the grain yield and quality of wheat. Plant-growth-promoting bacteria may help to improve plant Zn availability. This study evaluated the influence of inorganic Zn, with and without Zn-solubilising bacteria (Pseudomonas sp. MN12), on performance and grain biofortification of wheat. Zinc was supplied with and without Pseudomonas to two bread wheat (Triticum aestivum L.) cultivars (Lasani-2008 and Faisalabad-2008) via four treatments: soil application (5.0 mg kg–1 soil), foliar application (0.025 m), seed priming (0.5 m) and seed coating (1.25 g kg–1 seed). Hydroprimed seeds were taken as control. Inoculation with Pseudomonas improved photosynthesis, yield, biofortification of grains and organic acid production in root exudates. However, inoculation was more effective when applied in combination with different Zn application methods. Maximum improvement in plant photosynthetic assessment and grain yield was recorded with Pseudomonas + Zn seed priming, followed by Pseudomonas + soil application of Zn. These two combinations also enhanced organic acid production in root exudates of wheat. Soil and foliar application of Zn with Pseudomonas enhanced Zn concentration in whole grain, embryo, aleurone and endosperm. Combined application of Pseudomonas and Zn (soil and foliar) reduced phytate concentration and [phytate] : [Zn] ratio and increased the bioavailable Zn in wheat grain compared with the control. In conclusion, the combination Pseudomonas inoculation along with Zn seed priming and soil application was more effective in improving grain yield of wheat, whereas soil- and foliar-applied Zn with Pseudomonas inoculation was better in enhancing grain Zn concentration and bioavailability.