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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Crop Bioprotection Research » Research » Publications at this Location » Publication #375620

Research Project: Development of New Production Methodologies for Biocontrol Agents and Fastidious Microbes to Improve Plant Disease Management

Location: Crop Bioprotection Research

Title: Resistance of a Halobacterium salinarum isolate from a solar saltern to cadmium, lead, nickel, zinc, and copper

item BAATI, HOUDA - University Of Sfax
item SIALA, MARIEM - University Of Sfax
item AZRI, CHAFAI - University Of Sfax
item AMMAR, EMNA - University Of Sfax
item Dunlap, Christopher
item TRIGUI, MOHAMED - University Of Sfax

Submitted to: Antonie Van Leeuwenhoek
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/16/2020
Publication Date: 9/24/2020
Citation: Baati, H., Siala, M., Azri, C., Ammar, E., Dunlap, C.A., Trigui, M. 2020. Resistance of a Halobacterium salinarum isolate from a solar saltern to cadmium, lead, nickel, zinc, and copper. Antonie Van Leeuwenhoek. 113:1699–1711.

Interpretive Summary: An ARS researcher from Peoria, Illinois, collaborated with scientists from a University in Tunisia to characterize a novel isolate of Archaea from a high salt environment. Archaea are a class of microorganisms similar to bacteria and play multiple ecological roles in the environment. This strain was isolated from a heavy metal contaminated high salt environment with the expectation it would be able to tolerate the high salt stress and heavy metal stress. The isolate was shown to have high salt and heavy metal tolerance. The strain was determined to be the most tolerant of lead and cadmium of the heavy metals tested. High salt and heavy metal contamination are a significant problem worldwide in irrigated agricultural lands. Understanding how microorganisms tolerate these stresses improves our knowledge of how these stresses impact the microbial ecology of irrigated soils.

Technical Abstract: The current study focuses on the tolerance of a strain of Halobacterium salinarum isolated from Sfax solar saltern (Tunisia) towards cadmium, lead, nickel, zinc, and copper by using agar dilution methods in complex and minimal media. The results showed the least inhibitory metals based on Minimum Inhibitory Concentrations (MICs) were lead (MIC=4.5 mM), cadmium (MIC=4 mM), and nickel (MIC=2.5 mM) in complex medium. The MICs of these metals were more inhibitory (MIC < 2 mM) in the other tested media. The archaeal strain showed a high sensitivity for copper and zinc, with MICs below 0.5 mM for both metals. Growth kinetics in complex and minimal media showed the strain to be more sensitive to the metals in liquid media than in solid media. The growth kinetic assays showed the presence of selected heavy metals resulted in a lower growth rate and lower total cell mass relative to the control. Despite that cadmium and lead are nonessential and have no nutrient value, they were the most tolerated metals by H. salinarum strain. In addition, pigment production in the strain was inhibited by the presence of the heavy metals relative to the control.