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bioRxiv · 10.1101/2025.10.16.682883

Phenotypic and Molecular characterization of thermophlic bacterial isolates from the rizosphere of Panicum antidotale in Cholistan desert, Pakistan

Aslam, M.·Afzal, M.·Batool, R.·Rehman, T.·Nasim, F.-u.-h.·Ejaz, S.
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Abstract

The major aim of this study was to isolate, characterize, and determine the distribution of culturable bacteria in the rhizosphere of Panicum antidotale (PAMA) from the Cholistan desert, Pakistan. A total of 109 thermophilic bacterial isolates were obtained from PAMA and subjected to morphological, biochemical, and molecular characterization at The Islamia University of Bahawalpur. Standard protocols were used for physical and biochemical analysis, while molecular identification involved 16S rRNA profiling, restriction fragment length polymorphism (RFLP), and DNA sequence analysis. PCR amplicons of selected isolates with distinct RFLP patterns were sequenced, and the DNA sequences were analyzed using BLAST to determine species identity. Results revealed the presence of Bacillus subtilis, Brevibacillus borstelensis, and Paenibacillus dendritiformis in the majority of analyzed rhizosphere samples. Bacillus licheniformis and Bacillus subtilis were the most dominant species in PAMA, accounting for 45% and 30% of the isolates, respectively. In addition, lower frequencies of other species, such as Paenibacillus dendritiformis (10-15%), were also observed. These findings demonstrate that Panicum antidotale supports a unique rhizospheric bacterial community dominated by thermophilic Bacillus species. This study represents the first comprehensive investigation of PAMA microbiota in the Cholistan desert. The results provide novel insights into bacterial diversity in extreme environments and highlight the potential role of these communities in plant growth promotion and stress adaptation. Further studies are warranted to explore the ecological significance and possible biotechnological applications of PAMA-associated thermophilic bacteria for sustainable agriculture and environmental management. ImportanceThis study presents the first molecular-level investigation of thermophilic bacterial communities inhabiting the rhizosphere of Panicum antidotale in the Cholistan Desert, Pakistan. Through combined phenotypic, biochemical, and molecular analyses, diverse thermophilic Bacillus, Brevibacillus, and Paenibacillus species were identified as dominant members of this extreme arid ecosystem. These bacteria possess plant growth-promoting and stress-alleviating traits, underscoring their ecological significance in supporting desert plant resilience. Importantly, this first molecular characterization of P. antidotale-associated microbiota reveals that these isolates may also serve as promising sources of valuable enzymes and bioactive metabolites. The findings broaden our understanding of microbial diversity in arid rhizospheres and highlight the potential applications of these thermophilic bacteria in sustainable agriculture, biotechnology, and environmental management.

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Aslam, M., Afzal, M., Batool, R., Rehman, T., Nasim, F.-u.-h., Ejaz, S.. 2025-10-17. Phenotypic and Molecular characterization of thermophlic bacterial isolates from the rizosphere of Panicum antidotale in Cholistan desert, Pakistan. https://doi.org/10.1101/2025.10.16.682883

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