Effect of ACC-deaminase positive rhizobacteria on maize crop under drought and salt affected conditions

Muhammad Zafar-ul-Hye¹, Hafiz Muhammad Farooq¹ and Zahir Ahmad Zahir²

¹Department of Soil Science, University College of Agriculture, Bahauddin Zakariya University, Multan, Pakistan

²Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan

Ethylene is an important phytohormone. Its presence in plants is thought to be essential for normal growth. When endogenous concentration of ethylene increases, especially during stress conditions like drought, salinity etc., it produces deleterious effects on plant growth. To overcome this problem, there may be certain chemical and biological techniques. Being environmental friendly, biological techniques are considered as more useful as compared to chemical approaches. The rhizobacteria containing 1-aminocyclopropane-1-carbyxylate deaminase (ACC-deaminase) have been found to be involved in decreasing endogenous concentration of ethylene. It is established that 1-aminocyclopropane-1-carbyxylic acid (ACC) is an immediate precursor of ethylene biosynthesis in higher plants in methionine pathway. The rhizobacteria containing ACC-deaminase possess potential to convert the ACC into ammonia and α-ketobutyrate and reduce endogenous biosynthesis of ethylene. So, reduction in endogenous level of ethylene in plants removes its deleterious effects on growth and improved plant growth may be achieved even under stress conditions. Keeping in view all these facts, fabrics of a field  experiment were woven to investigate the effects of two ACC-deaminase positive rhizobacterial strains on growth and yield of maize crop under salt affected conditions in reference to drought stress. It was surprising to note that ACC-deaminase positive rhizobacteria significantly promoted plant growth in dual stress conditions i.e., drought and salt affected conditions. So it was concluded from the field study that ACC-deaminase positive rhizobacteria have tremendous potential to reduce stress ethylene biosynthesis and ultimately improve growth of plants under drought and salt-affected conditions.