Vol. 11, Special Issue 7 (2022)

Author(s):
C Ushamalini, A Balasubramanian, KS Anjali, M Tilak, N Indra, Dr. G Swathiga and Manimaran V

Abstract:
Plant growth promoting rhizobacteria (PGPR) are a diverse set of bacteria found in the rhizosphere, on root surfaces, and in close proximity to roots that can directly or indirectly promote the extent or quality of plant development. Rhizobacteria that promote plant growth include rhizosphere-colonizing N2-fixing rhizobacteria that provide nitrogen to plants, as well as the well-known symbiosis of legume rhizobia. Several bacteria, including Pseudomonas, Azospirillum, Azotobacter, Klebsiella, Enterobacter, Alcaligens, Arthobacter, Burkholderia, Bacillus, and Serratia, have been found to improve plant development in recent decades. Rhizobium is the most important PGPR, which is able to develop a symbiotic association with its specific host plant and increase its growth and yield by biologically fixing atmospheric nitrogen. However, the other PGPR, such as Pseudomonas and Bacillus, are able to increase plant growth and yield production by colonizing the host plant roots in a nonsymbiotic manner. PGPR's direct promotion entails either providing the plant with a plant growth promoting substance or providing the plant with a plant growth promoting substance. When PGPR inhibits the harmful effects of one or more phytopathogenic microorganisms, it indirectly promotes plant growth. In response to PGPR inoculation, significant increases in growth and yield of agronomically important crops have been recorded. Bacterial inoculants can boost plant growth and germination, improve seedling emergence, improve responses to stress, and protect plants from disease. When compared to farmed crops, the impact of PGPR on trees has received the least attention. The current review focuses on PGPR's mode of action and growth-promoting activities in trees.