NaCl Modifies Biochemical Traits in Bacterial Endophytes Isolated from Halophytes: Towards Salinity Stress Mitigation...

Area of Science:

• Microbiology
• Plant Science
• Environmental Science

Background:

• Soil salinity is a growing threat to agriculture due to climate change.
• Halophytes harbor diverse bacterial endophytes with potential for plant growth promotion.
• Understanding the biochemical capabilities of these endophytes is crucial for their application.

Purpose of the Study:

• To isolate and identify bacterial endophytes from six halophyte species.
• To characterize their plant growth-promoting traits, including nutrient solubilization and enzyme production.
• To assess their salt tolerance and the role of organic acids and sugars in their functions.

Main Methods:

• Isolation and molecular identification of 120 bacterial endophytes.
• Characterization of indole acetic acid (IAA), exopolysaccharides (EPS), and siderophores (SID) production.
• Assays for phosphate, potassium, zinc, and manganese solubilization, phytate mineralization, and enzymatic activities (phosphatases, phytases, xylanases, chitinases) under varying NaCl concentrations.

Main Results:

• Eleven halotolerant endophytes (up to 2.5 M NaCl) were identified, including species of *Bacillus*, *Halomonas*, *Pseudomonas*, and *Oceanobacillus*.
• Significant variations in nutrient solubilization and enzymatic activities were observed, influenced by NaCl presence.
• Organic acids (tartaric, maleic, vanillic) and sugars (fructose) were implicated in nutrient solubilization and mineralization.

Conclusions:

• Bacterial endophytes from halophytes possess diverse biochemical mechanisms for nutrient acquisition and stress tolerance.
• These traits, particularly nutrient solubilization via organic acids and sugars, are influenced by salinity.
• Further in vivo studies and consortium testing are recommended to explore their potential for mitigating saline stress in crops under climate change.