Role of Nitrogen-Fixing Plant Growth-Promoting Rhizobacteria in Sustainable Production of Vegetables: Current Perspective

Abstract

Vegetables due to high nutritional value comprising of carbohydrates, proteins, vitamins and several other essential elements are considered one of the important dietary constituents. In order to achieve optimum yields, agrochemicals are frequently used in vegetable cultivation. However, the excessive and inappropriate use of agrochemicals has been found deleterious for both soil fertility and vegetable production. The negative impact of agrochemicals in vegetable production practices can be avoided by the use of biofertilizers involving nitrogen-fixing plant growth-promoting rhizobacteria. The use of non-pathogenic nitrogen-fixing plant growth-promoting rhizobacteria to enhance vegetable production is, therefore, currently considered as a safe, viable and inexpensive alternative to chemical fertilization. Even though there are no direct connections between nitrogen-fixing organisms and vegetables, both symbiotic and asymbiotic/associative nitrogen-fixing bacteria have been used to facilitate the growth and yield of non-legume crops like vegetables through mechanisms other than nitrogen fixation. Indeed, there are numerous reports on the effect of plant growth-promoting rhizobacteria on vegetable production, but the information on nitrogen-fixing bacteria employed in vegetable production is scarce. Considering these gaps and success of nitrogen-fixing bacteria application in vegetable production achieved so far, efforts have been directed to highlight the impact of nitrogen fixers on the production of vegetables. Here, efforts will be made to identify most suitable nitrogen fixers which could be used to improve the health and quality of vegetables grown in different regions. The use of nitrogen fixers is also likely to reduce the use of chemicals in vegetable production.