Exploring the Role of Iron-Solubilizing Bacillus sp. for Promoting Cereal Growth

Azhar Hussain^1*Maryam Saeed¹Abubakar Dar¹Hammad Anwar¹Muhammad Imran²Hossam El-Beltagi^3*Usman Zulfiqar⁴Obidjon Abdulloev⁵Nazih Y. Rebouh⁶P. V. Vara Prasad^7*

• ¹Department of Soil Science, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
• ²Soil & Environmental Sciences Division, Nuclear Institute for Agriculture and Biology, Faisalabad, Pakistan
• ³Agricultural Biotechnology Department, King Faisal University College of Agricultural and Food Sciences, Al Ahsa, Saudi Arabia
• ⁴The Islamia University of Bahawalpur Pakistan Department of Agronomy, Bahawalpur, Pakistan
• ⁵Department of Chemistry, Andijan State University, Andijan, Uzbekistan
• ⁶Department of Environmental Management, Institute of Environmental Engineering, Rossijskij universitet druzby narodov, Moscow, Russia
• ⁷Department of Agronomy, Kansas State University, Manhattan, United States

Iron (Fe), being the most limited micronutrient in soils, performs key functions in plant's physiology viz., enzyme activation and chlorophyll synthesis. Its deficiency prevails in humans in the form of disorder in pregnant women and children e.g. anaemia. Therefore, the current investigation aims at isolation, screening, characterization, identification of Fe-solubilising bacteria and their impact on maize and wheat growth under axenic conditions. The results depicted their differential response against siderophores and exopolysaccharide production, urease activity, phosphorus and zinc solubilization. Under axenic conditions, the maximum increase in wheat shoot, root length, chlorophyll a, b and carotenoids contents under AH-22 isolates was observed which was 67.2, 34.6, 24.7, 30.1, 41.7% higher than the control, respectively. Similarly, maximum increase of 41.8, 41.7, 37.2, 37, and 16.4%, respectively, was recorded in maize shoot and root lengths, chlorophyll a, b and carotenoids contents under AH34 strain inoculated treatment. Furthermore, the molecular identification of the promising rhizobacteria depicted AH-22 as Bacillus subtilis, AH-26, AH-36, AH-46 as Bacillus sp. and AH-34 as Bacillus megaterium strain. On the nasis of the mentioned results it can be concluded that rhizobacterial strains Bacillus subtilis (AH-22) in wheat and Bacillus megaterium (AH-34) in maize effectively enhanced wheat and maize growth by improving nutrient solubilization and physiological traits. Moreover, the studied strains need to be tested in natural field conditions and the development of certain formulations to boost growth and Fe-biofortification in cereals.