Zn-mobilizing bacteria improve shoot biomass and zinc content in wheat

Enhancing zinc (Zn) content in wheat grains by using Zn-mobilizing rhizosphere bacteria is becoming an eco-friendly and sustainable alternative to conventional approaches such as chemical fertilization. Our study aimed to isolate, screen and evaluate Zn-mobilizing rhizosphere bacteria to improve its content in wheat biomass. Wheat rhizosphere soils were collected in several wheat planted soils in Ethiopia and Zn-solubilizing bacteria were isolated and screened for their plant beneficial traits. Isolates W8_A, W25_A and W63_B were selected. Pot experiments were conducted in sterilized river sand supplemented with 0.05% zinc oxide by using these isolates. The experiment consisted of nine treatments in complete randomized design with four replications. Data were means of three independent experiments. W8_A, W25_A and W63_B exhibited zinc solubilization index > 4.0. Consortium inoculation showed the highest improvements in plant growth. Inoculations improved shoot length and dry weigh on average by 67.4% and 84.2%, respectively compared to the control. On average, 90.2% root and 75.5% shoot Zn content increased compared to the untreated control. Hence, the isolates can be applied for Zn bio-fortification in wheat to combat Zn deficiencies in food grains.