Unveiling the Plant Growth-Promoting Potential of Rhizobacteria from Underutilized Crops of Talinum triangulare and Celosia argentea for Sustainable Agriculture

Underutilized crops are plant species possessing significant potential for cultivation, medicinal applications, and human consumption which are often overlooked within mainstream agriculture and food systems. This study aimed to isolate and characterize plant growth-promoting bacteria (PGPB) from the rhizospheres of two underutilized crops of Talinum triangulare and Celosia argentea, assessing their capacity to enhance plant growth. There is paucity of information on bacterial communities associated with these nutrient rich vegetables. Bacterial isolates were obtained from soil samples collected from the respective rhizosphere and screened for key plant growth-promoting traits, including nitrogen fixation, phosphate solubilization, siderophore production and indole-3-acetic acid (IAA) synthesis. A total of 26 bacterial strains were characterized biochemically, while the isolates showing the highest performance for the plant growth promoting traits were identified using 16S rRNA sequencing. All the 26 isolates had the potential to produce ammonium and fix nitrogen. However, isolate TEe recorded the highest concentration of IAA (0.080 mg/ml), isolate TEd showed the highest phosphate solubilization index of 236%, and isolate WL11 produced the maximum siderophoric unit of 70.09%. Based on the in-vitro characterization of the isolates for plant growth promotion, isolates TEe, TEh, WL6, and WL7 exhibited increased potential to enhance plant growth and were subsequently identified as Bacillus licheniformis, Pseudomonas aeruginosa, Bacillus cereus, Providencia stuartii respectively. The findings suggest that the rhizosphere of these vegetables harbor a diverse community of PGPB capable of promoting plant growth and nutrient uptake. Consequently, this study highlights the potential for utilizing bacteria as bio-inoculants in sustainable agricultural practices. Future research should focus on evaluating the performance of these isolates under field conditions and assessing their long-term effects on soil health and crop yield.