# Streptomyces spp. in Arid and Savannah Ecosystems: Effects on the Inhibition of Actinomycetoma Pathogens

## TL;DR

This study compares Streptomyces bacteria in arid and savannah soils and finds that those in arid regions are more effective at inhibiting a pathogen linked to actinomycetoma.

## Contribution

The study demonstrates that Streptomyces from arid ecosystems have higher inhibitory potential against Streptomyces sudanensis compared to those from savannahs.

## Key findings

- Arid ecosystem isolates showed a higher mean inhibition value (2.8411) compared to savannah isolates (1.7139).
- Statistical analysis confirmed a significant difference in inhibition (t = 2.589, p = 0.0126).
- Arid soils had higher temperatures and lower rainfall compared to nutrient-rich savannah soils.

## Abstract

Background

Knowledge of the ecological and soil differences between arid and savannah ecosystems is essential for assessing their biodiversity and potential for agricultural and disease-controlling applications. Arid zones are characterized by extreme temperatures and limited rainfall, supporting unique soil types that influence microbial communities. This study examined soil Streptomyces spp., known for their antibiotic properties, focusing on their inhibitory effects against Streptomyces sudanensis, a pathogen associated with actinomycetoma.

Methodology

Soil samples (n = 7) were collected, and physicochemical parameters, along with enzyme activities, were analyzed. Streptomyces spp. were isolated, characterized morphologically and phenotypically, and identified molecularly via 16S rRNA gene sequencing. Their inhibitory effects against S. sudanensis were evaluated using agar-based bioassays.

Results

Streptomyces spp. (n = 64), including Streptomyces griseostramineus, were identified. The results indicated significant ecological differences: arid sites had high temperatures (29.7°C) and low rainfall (70 mm) with nutrient-poor Yermosols, whereas savannah sites had higher rainfall (501 mm) and nutrient-rich Arenosols and Vertisols. Inhibition zones varied significantly, with arid ecosystem isolates showing a higher mean inhibition value (2.8411) compared to savannah isolates (1.7139). Statistical analysis verified a significant difference in mean inhibition (t = 2.589, p = 0.0126), suggesting distinct inhibitory capacities linked to the ecosystem.

Conclusions

This study emphasizes the significant ecological and soil differences between the ecosystems and proves that soil Streptomyces spp. in arid regions possess distinctly higher inhibition potential against S. sudanensis, suggesting their potential as biological agents in these environments.