Potential of Rhizosphere Microbes (Bacillus subtilis, Lactobacillus, Pseudomonas fluorescens, Azotobacter, and Streptomyces) as Bioprotectant Agents in Rice Plant Protection

Abstract

Rice production faces increasing pressure from pathogens and declining soil quality, creating the need for sustainable biological protection strategies. This study evaluated the functional roles and interaction mechanisms of rhizosphere microbial consortia in improving rice resistance and growth through a systematic literature review following PRISMA guidelines. A total of 62 peer-reviewed articles published between 2020 and 2024 in Scopus-indexed Q1 and Q2 journals were analyzed. The review identified major microbial genera, including Bacillus, Pseudomonas, Streptomyces, Lactobacillus plantarum, and Azotobacter, as important bioprotective agents in rice systems. These microbes suppress pathogens through antibiosis, siderophore-mediated Fe3+ competition, and induced systemic resistance (ISR) activation involving jasmonic acid, ethylene, and salicylic acid signaling pathways. Several strains also promote plant growth through nitrogen fixation and phytohormone production, particularly indole-3-acetic acid. Functional DNA markers such as srfAA, phlD, and chiA support targeted strain selection and improve the development of precision bioformulations. Multi-species microbial consortia generally provide more stable pathogen suppression than single strains under variable environmental conditions. Rhizosphere microbial consortia therefore represent a promising strategy for sustainable rice protection within Integrated Pest Management systems.