Soil–Plant–Microbe Interactions: Use of Nitrogen-Fixing Bacteria for Plant Growth and Development in Sugarcane

Sugarcane is an important industrial agricultural crop cultivated worldwide for the production of sugar, ethanol, and other related by-products. More than 50 diseases were observed in sugarcane caused by different plant pathogenic microbes, i.e., fungi, bacteria, viruses, phytoplasmas, and nematodes. Sugarcane is a lengthy crop, so it requires more amounts of plant nutrients, i.e., N, P, and K, as well as other micro- and macronutrients. Thus, the chances of diseases are more to adapt the favorable conditions for pathogens survival. Nitrogen is one of the greatest limiting nutritional aspects for the growth of plants. An abundant supply of nitrogen is required for the plant’s early growth. Higher doses of fertilizers, chemicals, and pesticides are applied by farmers to sugarcane to promote early growth and development of crops, to control the diseases, and to increase the yield in many countries. But the continuous use of these chemicals leads to resistance development against the pathogens and may cause negative effects on the environment and contamination of soil and water in addition to a serious hazard to human and animal health. Because of these facts, we focus to find an alternative method for chemical usage. It has been acknowledged that a large number of naturally occurring plant growth-promoting nitrogen-fixing microbes are present in soil/rhizosphere. A wide variety of mechanisms are used by these bacteria to colonize in the rhizosphere such as biological control against plant pathogens, biological nitrogen fixation, and phytohormone production, as well as their ability to enhance nutrient availability. A biological nitrogen-fixing microbe has massive potential to replace the chemical fertilizers and can be used as biofertilizer in plants. In this chapter, the role of bacteria associated with nitrogen fixation and colonizing the internal parts of the sugarcane plant without exerting any core destruction to their host plant is described.