Identification of Rhizobacteria in Microbiome of Cowpea (Vigna unguigulata L. Walp) From North West Province, South Africa

The rhizosphere microbiome is occupied by a variety of environmentally friendly microorganisms involved in plant health and environmental sustainability, however the knowledge is limited. It has been hypothesized that the plant growth promoting rhizobacteria has the greatest influence on plant growth since this population can respond quickly to increased nutrients. 40 bacterial strains were isolated from 12 soil samples collected from various sites of North-West Province, South Africa. The bacterial isolates were biochemically and culturally characterized for plant growth-promoting traits using conventional methods. Results revealed that 89% were positive for phosphate solubilisation, 47% siderophore production, 88% indole acetic acid production, 76% chitinolytic activity, 100% ammonia production and 82% hydrogen cyanide production. Phylogenetic and molecular evolutionary analyses were conducted. Nucleotide sequences were compared to the basic local alignment search tool database of sequences deposited at the National Centre for Biotechnology Information (NCBI) and corresponding nucleotide sequences retrieved from GenBank, revealed more than 95 percentage similarities. The bacterial strains were identified by the 16S rDNA gene sequencing as Bacillus species. The study suggests that these rhizobacteria might prove beneficial towards crop production and conservation in agriculture. Moreover, they are likely to be potential candidates for biofertilizers. Strategies that aim at more efficient utilization of soil resources would secure food production. Therefore, identifying novel growth promoting genes that can be used to explore other species genetically so as to promote their potential of contributing to agricultural crop development mostly in arid environments is of paramount importance.

Keywords: Agriculture, cowpea, microbiome, rhizosphere