Zinc-Solubilizing Microbes for Sustainable Crop Production: Current Understanding, Opportunities, and Challenges

Abstract

Zinc (Zn) is an essential and prime micronutrient needed in diminutive amount by agricultural crops for complete growth and development. It acts as an essential and key constituent of a variety of enzymatic reactions, carbohydrate metabolism, synthesis of proteins and auxin, and maintenance of cellular membrane veracity in plants. Zn is also an essential element in human diet as its deficiency affects normal development and functioning of nervous, immune, and skeletal systems. Crop plants and their consumable parts serve as major sources of Zn in human diet. Plants can uptake Zn as divalent cation, but a major portion of it exists in insoluble form in the soil and very little Zn becomes available to the plants. There are wide varieties of microbes which employ myriads of biological processes to make Zn available to plants from unavailable sources. These zinc-solubilizing microbes (ZSM) can be utilized as prospective alternatives to conventional less-efficient fertilizer application for enhancing Zn availability in soils. Owing to the naturally available source of Zn in soil and high cost of synthetic Zn fertilizers, the demand of ZSM is escalating with time. The injudicious application of chemical fertilizers can be minimized by using ZSM in crop production that can lead to environmental and agricultural sustainability. At the global level, several researchers have recognized the importance of ZSM for crop growth, health, and development. The current article illustrates the role of ZSM in improving plant production in an economical, environment-friendly, and sustainable manner. The mechanisms used by ZSM for Zn solubilization have been explained. An attempt has been made to provide a comprehensive global overview of research initiatives made in the field of sustainable crop production through ZSM, and further opportunities and challenges for use of ZSM-based technology in agriculture have been discussed.