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ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Plant Symbiotic Interactions
Volume 15 - 2024 |
doi: 10.3389/fpls.2024.1458540
This article is part of the Research Topic Use of Biostimulants in Beneficial Plant-Microbe Interactions View all 6 articles
Mitigation of salt stress in Sorghum bicolor L. by the halotolerant endophyte Pseudomonas stutzeri ISE12
Provisionally accepted- 1 Department of Geobotany and Landscape Planning, Nicolaus Copernicus University in Toruń, Toruń, Poland
- 2 Department of Microbiology, Nicolaus Copernicus University in Toruń, Toruń, Poland
- 3 Department of Biochemistry, Nicolaus Copernicus University in Toruń, Toruń, Poland
Increasing soil salinity, exacerbated by climate change, threatens seed germination and crop growth, causing significant agricultural losses. Using bioinoculants based on halotolerant plant growth-promoting endophytes (PGPEs) in modern agriculture is the most promising and sustainable method for supporting plant growth under salt-stress conditions. Our study evaluated the efficacy of Pseudomonas stutzeri ISE12, an endophyte derived from the extreme halophyte Salicornia europaea, in enhancing the salinity tolerance of sorghum (Sorghum bicolor L.). We hypothesized that P. stutzeri ISE12 would improve sorghum salt tolerance to salinity, with the extent of the increase in tolerance depending on the genotype's sensitivity to salt stress. Experiments were conducted for two sorghum genotypes differing in salinity tolerance (Pegah - salt tolerant, and Payam - salt sensitive), which were inoculated with a selected bacterium at different salinity concentrations (0, 100, 150, and 200 mM NaCl). For germination, we measured germination percentage and index, mean germination time, vigour, shoot and root length of seedlings, and fresh and dry weight. In pot experiments, we assessed the number of leaves, leaf area, specific leaf area, leaf weight ratio, relative root weight, plantlet shoot and root length, fresh and dry weight, proline and hydrogen peroxide concentrations, and peroxidase enzyme activity. Our study demonstrated that inoculation significantly enhanced germination and growth for both sorghum genotypes. The salinity-sensitive genotype (Payam) responded better to bacterial inoculation during germination and early seedling growth stages, showing approximately 1.4 to 1.8 times greater improvement than the salinity-tolerant genotype (Pegah). Payam also displayed better performance at the plantlet growth stage, between 1.1 and 2.6 times higher than Pegah. Furthermore, inoculation significantly reduced hydrogen peroxide, peroxidase activity, and proline levels in both sorghum genotypes. These reductions were notably more pronounced in Payam, with up to 1.5, 1.3, and 1.5 times greater reductions than in Pegah. These results highlight the efficacy of P. stutzeri ISE12 in alleviating oxidative stress and reducing energy expenditure on defense mechanisms in sorghum, particularly benefiting salt-sensitive genotypes. Our findings highlight the potential of the bacterial endophyte P. stutzeri ISE12 as a valuable bioinoculant to promote sorghum growth under saline conditions.
Keywords: endophytic bacteria, halophyte, Halotolerant bacteria, plant growth promoting bacteria, salt stress, Sorghum bicolor L. Moench
Received: 02 Jul 2024; Accepted: 02 Sep 2024.
Copyright: © 2024 Rajabi Dehnavi, Piernik, Ludwiczak, Szymańska, Ciarkowska, Cárdenas Pérez and Hrynkiewicz. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Ahmad Rajabi Dehnavi, Department of Geobotany and Landscape Planning, Nicolaus Copernicus University in Toruń, Toruń, Poland
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