Comparison of Two <i>Bacillus</i> Strains Isolated from the Coastal Zone in Barley (<i>Hordeum vulgare</i> L.) Under Salt Stress
Salt stress is one of the most important abiotic stress factors that negatively affects sustainable crop production, agricultural productivity, and microbial life. Increasing salt stress negatively affects the growth and development of barley, posing a threat to global food security. It is now known...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-02-01
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| Series: | Plants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2223-7747/14/5/723 |
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| Summary: | Salt stress is one of the most important abiotic stress factors that negatively affects sustainable crop production, agricultural productivity, and microbial life. Increasing salt stress negatively affects the growth and development of barley, posing a threat to global food security. It is now known that inoculation of plant growth-promoting rhizobacteria (PGPR) has significant potential in increasing stress tolerance and yield in agricultural products. This study focused on the effects of <i>Bacillus cereus</i> CUN6 and <i>Bacillus thuringiensis</i> SIRB2, isolated from the coastal zone and tested for their PGPR capacities, on physiological (root length, shoot length, biomass, dry weight) and biochemical (total chlorophyll, total protein, hydrogen peroxide, lipid peroxidation, peroxidase activity (POX), catalase activity (CAT)) analyses in <i>Hordeum vulgare</i> L. seedlings under salt stress. The results showed that the two bacterial inoculations alleviated the negative effects of salt stress by increasing the root-shoot length, biomass, dry weight, chlorophyll content, and total protein content in barley plants. However, <i>B.</i><i>thuringiensis</i> increased growth and development especially in root length, biomass, and dry weight compared to <i>B.</i><i>cereus.</i> On the other hand, <i>B.</i><i>cereus</i> significantly increased root length, biomass, and chlorophyll content under salt stress; these increases were 17%, 5%, and 7%, respectively. <i>B.</i><i>thuringiensis</i> chlorophyll content increased by 4% in 300 mM NaCl compared to the control. When compared in terms of the antioxidant defense system, <i>B.</i><i>thuringiensis</i> inoculation was more effective on CAT activity, while <i>B.</i><i>cereus</i> inoculation was more effective on POX activity. Under salt stress, <i>B.</i><i>cereus</i> and <i>B.</i><i>thuringiensis</i> inoculation significantly decreased H<sub>2</sub>O<sub>2</sub> content in barley; these decreases were 16% and 10%, respectively. Additionally, TBARs content was significantly decreased by <i>B.</i><i>cereus</i> and <i>B.</i><i>thuringiensis</i> inoculation under salt stress; these decreases were determined as 8% and 9%, respectively, compared to the control. These results indicated that both bacterial inoculations can alleviate the salt tolerance of barley seedlings by regulating antioxidant metabolism. This research focused on the potential of <i>B.</i><i>cereus</i> and <i>B.</i><i>thuringiensis</i> as biofertilizers against salt stress in barley based on physiological and biochemical analysis. |
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| ISSN: | 2223-7747 |