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Introduction
The soil layer around plant roots, known as the rhizosphere, is critical to plant growth and development.1, 2 Rhizobacteria are bacterial communities that live in this region, and some of them, known as plant growth-promoting rhizobacteria (PGPR), have a favourable impact on plant growth. These PGPR promote plant growth directly or indirectly.3 These helpful rhizobacteria are classified into various genera, including Bacillus, Azotobacter, and Pseudomonas.
Bacillus is a genus of gram-positive bacteria commonly found in soil, with species such as Bacillus subtilis.4 being diazotrophic. Extensive research has been conducted on the ability of Bacillus and Paenibacillus species to promote plant growth. 5, 6 It is well established that B. cereus, B. subtilis, and B. megaterium can serve as effective biocontrol agents against plant diseases. Additionally, antifungal peptides produced by species of Bacillus have the ability to regulate fungal growth.7
PaenibacillusandBacillus are widely found in the rhizosphere. Very little information is available about this genus, but it is impossible that only a single species will dominate and outnumber other species in most soils.8 Many PGPR possess great potential as inoculants, and they can be used for agricultural purposes and environmental protection. These PGPR help to maintain the sustainability of agroecosystems. However, currently, PGPR are not effectively used in agriculture despite many positive reports in laboratory conditions. The use of a consortium of PGPR with different plant growth-boosting features can have a greater favourable impact on plant growth than using a single strain of PGPR. Inoculation of plants with mixed strains was found to be more effective than using a single strain.9 As a result, the purpose of this study was to determine the influence of a Bacillus sp. consortium on plant growth promotion.
Materials and Methods
Isoaltion and Characterization of Bacillus sp
Bacillus sp.from the rhizospheric zone were isolated as previously described.10 Colonies isolated were examined for their cell shape, gram reaction, and ability to form endospores.11 Bacillusspecies were identified as previously described. 12 Different biochemical tests were performed, such as arginine hydrolysis, catalase test, lipid hydrolysis, casein hydrolysis, gelatin liquefaction, starch hydrolysis, and urease test.