Pseudoxanthomonas sp. JBR18, a halotolerant endophytic bacterium, improves the salt tolerance of Arabidopsis seedlings

• Published in: Plant physiology and biochemistry Vol. 207; p. 108415
• Main Authors: Peng, Yuxin, Jiang, Lingmin, Jeon, Doeun, Cho, Donghyun, Kim, Youngmin, Kim, Cha Young, Lee, Ju Huck, Lee, Jiyoung
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.02.2024
• Subjects: Arabidopsis - genetics; Bacteria; Halophyte-associated endophytic bacterium; Plant growth-promoting bacteria; Salt stress; Salt Tolerance; Seedlings - physiology; Strain JBR18; Stress, Physiological - genetics; R2A; NBT; Salt stress; Strain JBR18; GUS; POD; MS; qRT-PCR; CK; IAA; EPS; SOD; MDA; PGPB; ST-PGPB; DCFH-DA; Plant growth-promoting bacteria; Halophyte-associated endophytic bacterium; ANOVA; CAT; ROS
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2024.108415

Salinization of land is globally increasing due to climate change, and salinity stress is an important abiotic stressor that adversely affects agricultural productivity. In this study, we assessed a halotolerant endophytic bacterium, Pseudoxanthomonas sp. JBR18, for its potential as a plant growth-promoting agent with multiple beneficial properties. The strain exhibited tolerance to sodium chloride concentration of up to 7.5 % in the R2A medium. In vitro evaluation revealed that strain JBR18 possessed proteolytic, protease (EC 3.4), and cellulase (EC 3.2.1.4) activities, as well as the ability to produce indole-acetic acid, proline, and exopolysaccharides. Compared with the controls, co-cultivation of Arabidopsis seedlings with the strain JBR18 improved plant growth, rosette size, shoot and root fresh weight, and chlorophyll content under salinity stress. Moreover, JBR18-inoculated seedlings showed lower levels of malondialdehyde, reactive oxygen species, and Na+ uptake into plant cells under salt stress but higher levels of K+. Additionally, seedlings inoculated with JBR18 exhibited a delayed response time and quantity of salt-responsive genes RD29A, RD29B, RD20, RD22, and KIN1 under salt stress. These multiple effects suggest that Pseudoxanthomonas sp. JBR18 is a promising candidate for mitigating the negative impacts of salinity stress on plant growth. Our findings may assist in future efforts to develop eco-friendly strategies for managing abiotic stress and enhancing plant tolerance to salt stress. [Display omitted] •JBR18 significantly increased Arabidopsis biomass under salt and non-salt stress.•JBR18 inoculation stimulated indole-3-acetic acid production in Arabidopsis roots.•JBR18 decreased ROS leves and Na + ion uptake into plant cells under salt stress.•JBR18 reduced the salt stress response gene levels in Arabidopsis under salt stress.•JBR18 is a promising microbial agent that can mitigate the negative effects of salinity stress on plant growth.