The potential of Pseudomonas fluorescens as biological control agent against sheath blight disease in rice: a systematic review

Abstract

Rice is a staple food source for more than 3.5 billion people. However, rice production can be hampered by several factors and disease is one of them. Sheath blight disease caused by Rhizoctonia solani is a serious disease that can cause huge losses. Several control methods have been practised by rice growers to manage the disease; however, chemical fungicides remain a main preference. Unfortunately, heavy reliance on chemical fungicides could lead to many other problems including resistant development, environmental pollution, and harmful to non-target organisms and humans. Managing rice disease through biological control is considered an alternative approach. Exploration of Pseudomonas fluorescens as a biocontrol agent against rice disease pathogens is an explicit example of biological approach. The potential of this bacterium has been highlighted by many researchers. This review provides insight into the potential of P. fluorescens against R. solani in rice. Three databases were used to collect reliable articles with four keywords. The Preferred Reporting Items for the Systematic Reviews approach were used to systematically screen the research articles and evaluate eligibility and exclusion. A total of 5930 articles were found but only 22 articles were selected after eliminating the duplicate articles and further eligibility was screened based on title and abstract. The highest number of published articles on P. fluorescens as a bioagent to control sheath blight was from India. The agent was used either alone or in combination with seed, root, soil, and foliar treatments to control sheath blight. Most of the research findings showed the agent successfully reduced the disease severity, promoted plant growth and increased rice yield. However, there are obstacles to commercial P. fluorescens-based products due to the instability of the agent at different soil types. More intensive research works are needed to enhance the efficacy of the agent in the real environmental setting