Mitigation of salt stress in plants by the salt-tolerant bacterium Pantoea ananatis JBR3-16 isolated from sand sedge (Carex pumila Thunb.)

• Published in: Plant growth regulation Vol. 101; no. 2; pp. 489 - 502
• Main Authors: Peng, Yuxin, Jiang, Lingmin, Jeon, Doeun, Jeong, Jae Cheol, Kim, Youngmin, Kim, Cha Young, Lee, Ju Huck, Lee, Jiyoung
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.11.2023; Springer Nature B.V
• Subjects: Abiotic stress; Acetic acid; Agriculture; Bacteria; Biomedical and Life Sciences; Carex arenaria; Carex pumila; Catalase; Chlorophyll; Cultivation; Endophytes; Exopolysaccharides; Fluorescence; Gene expression; Genes; Halophytes; Hormones; Indoleacetic acid; Inoculation; Life Sciences; Mitigation; Original Paper; Pantoea ananatis; Plant Anatomy/Development; Plant bacterial diseases; Plant growth; Plant Physiology; Plant Sciences; Plants (botany); Reactive oxygen species; Rosette; Salinity tolerance; Salt tolerance; Sand; Sandy soils; Sodium chloride; Soil microorganisms; Strain; Plant growth-promoting bacteria; Reactive oxygen species; Salt stress; GUS stain
• ISSN: 0167-6903; 1573-5087
• DOI: 10.1007/s10725-023-01036-7

Salt stress is a major abiotic stress that limits plant growth, development, and productivity of crops. However, some salt-tolerant plant growth-promoting bacteria (ST-PGPB) can confer abiotic stress tolerance to plants. This study isolated 22 endophytic bacteria from the halophyte sand sedge ( Carex pumila Thunb.) cultivated on sandy beach soil. One of the bacterial isolates, strain JBR3-16, survived in R2A broth supplemented with 10% NaCl, showing various plant growth-promoting properties under salt conditions. The salt tolerance mechanism of strain JBR3-16 was investigated through fluorescent microscopy, analysis of growth characteristics, and gene expression. Inoculation of plants with strain JBR3-16 significantly improved the salt-induced reduction of rosette diameter, leaf and root fresh weights, and chlorophyll contents in 100 and 150 mM NaCl. Moreover, strain JBR3-16 promoted salt tolerance by stimulating the production of indole-3-acetic acid, exopolysaccharides, proline, and catalase activity when cultivated on 50–200 mM NaCl medium. Furthermore, reducing reactive oxygen species (ROS) and expressing key abiotic stress-related genes under salinity conditions were the primary resistance mechanisms to high salt concentrations in JBR3-16. Finally, CoroNa Green as a fluorescent Na + indicator was observed in the root tips under salt conditions but restricted by JBR3-16 co-cultivations. Our results revealed that ST-PGPB Pantoea ananatis JBR3-16 alleviates NaCl stress in plants by (1) inducing osmolytes and plant hormones, (2) lowering ROS generation and expression levels of salt-responsive genes, and (3) reducing Na + uptake into plants. This study provides an approach to comprehensively understand and evaluate ST-PGPR as a biological inoculant for plants under salt stress.