<abstract xmlns="http://www.w3.org/1999/xhtml"><p>The development of rhizobial inoculants with increased resistance to abiotic stress is critical to mitigating the challenges related to climate change. This study aims at developing a soybean stress-tolerant <italic>Bradyrhizobium</italic> inoculant to be used under the mixed stress conditions of acidity, high temperature, and drought. Six isolates of <italic>Bradyrhizobium</italic> with high symbiotic performance on soybean were tested to determine their growth or survival abilities under <italic>in vitro</italic> conditions. The representative stress-tolerant <italic>Bradyrhizobium</italic> isolates 184, 188, and 194 were selected to test their ability to promote soybean growth under stress conditions compared to the type strain <italic>Bradyrhizobium diazoefficiens</italic> USDA110. The plant experiment indicated that isolate 194 performed better in symbiosis with soybean than other <italic>Bradyrhizobium</italic> strains under stress conditions. Based on the stress tolerance index, soybeans inoculated with isolate 194 showed a high growth performance and significantly better nodulation competition ability than USDA110 under several stress conditions. Interestingly, supplementation of sucrose in the culture medium significantly enhances the survival of the isolate and leads to improved plant biomass under various stress conditions. Analysis of the intra-cellular sugars of isolate 194 supplemented with sucrose showed the accumulation of compatible solutes, such as trehalose and glycerol, that may act as osmoprotectants. This study indicates that inoculation of stress-tolerant <italic>Bradyrhizobium</italic> together with sucrose supplementation in a medium could enhance bacterial survival and symbiosis efficiency under stress conditions. Although it can be applied for inoculant production, this strategy requires validation of its performance in field conditions before adopting this technology.</p></abstract>

The development of rhizobial inoculants with increased resistance to abiotic stress is critical to mitigating the challenges related to climate change. This study aims at developing a soybean stress-tolerant Bradyrhizobium inoculant to be used under the mixed stress conditions of acidity, high temperature, and drought. Six isolates of Bradyrhizobium with high symbiotic performance on soybean were tested to determine their growth or survival abilities under in vitro conditions. The representative stress-tolerant Bradyrhizobium isolates 184, 188, and 194 were selected to test their ability to promote soybean growth under stress conditions compared to the type strain Bradyrhizobium diazoefficiens USDA110. The plant experiment indicated that isolate 194 performed better in symbiosis with soybean than other Bradyrhizobium strains under stress conditions. Based on the stress tolerance index, soybeans inoculated with isolate 194 showed a high growth performance and significantly better nodulation competition ability than USDA110 under several stress conditions. Interestingly, supplementation of sucrose in the culture medium significantly enhances the survival of the isolate and leads to improved plant biomass under various stress conditions. Analysis of the intra-cellular sugars of isolate 194 supplemented with sucrose showed the accumulation of compatible solutes, such as trehalose and glycerol, that may act as osmoprotectants. This study indicates that inoculation of stress-tolerant Bradyrhizobium together with sucrose supplementation in a medium could enhance bacterial survival and symbiosis efficiency under stress conditions. Although it can be applied for inoculant production, this strategy requires validation of its performance in field conditions before adopting this technology.

Enhancing the Efficiency of Soybean Inoculant for Nodulation under Multi-Environmental Stress Conditions

Polish Journal of Microbiology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

The development of rhizobial inoculants with increased resistance to abiotic stress is critical to mitigating the challenges related to climate change. This...

Enhancing the Efficiency of Soybean Inoculant for Nodulation under Multi-Environmental Stress Conditions

Article Category: original-paper

Publicado en línea: 06 dic 2021

Páginas: 257 - 271

Recibido: 29 oct 2020

Aceptado: 23 may 2021

DOI: https://doi.org/10.33073/pjm-2021-024

Palabras clave
nodulation competition, stress conditions, compatible solutes, osmoprotectant

© 2021 Jenjira Wongdee et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Enhancing the Efficiency of Soybean Inoculant for Nodulation under Multi-Environmental Stress Conditions

Article Category: original-paper

Publicado en línea: 06 dic 2021

Páginas: 257 - 271

Recibido: 29 oct 2020

Aceptado: 23 may 2021

DOI: https://doi.org/10.33073/pjm-2021-024

Palabras clavenodulation competition, stress conditions, compatible solutes, osmoprotectant

© 2021 Jenjira Wongdee et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Palabras clave
nodulation competition, stress conditions, compatible solutes, osmoprotectant