Salt-Tolerant Bacteria Help Tomato Plants Thrive in Salty Soil

Jenn Hoskins
6th July, 2024

Salt-Tolerant Bacteria Help Tomato Plants Thrive in Salty Soil

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Shandong Normal University found that Bacillus sp. strain RA helps tomato plants tolerate salt stress
  • The bacteria adapt to salty soils through specific genes and reprogramming energy metabolism
  • Myo-inositol, a metabolite in tomato leaves, promotes plant growth and shapes beneficial microbial communities under salt stress
Soil salinity is a significant global issue that threatens agricultural productivity. Researchers at Shandong Normal University have recently published a study[1] that investigates how a novel strain of plant growth-promoting rhizobacteria (PGPR), Bacillus sp. strain RA, can enhance tomato plant tolerance to salt stress. This research delves into the genomic and metabolic characteristics of strain RA, offering new insights into its role in promoting salt tolerance in plants. The study begins by addressing the problem of soil salinity, which affects crop yields worldwide. PGPRs are known to help plants adapt to various stresses, including high salinity. However, the mechanisms by which these bacteria confer salt tolerance to plants have been largely unexplored. The researchers focused on Bacillus sp. strain RA, a halotolerant PGPR, to understand its genomic adaptations and how it aids tomato plants in coping with salt stress. Comparative genomic analysis revealed that strain RA exhibits a high level of evolutionary plasticity. This plasticity is facilitated by strain-specific genes and evolutionary constraints driven by purifying selection, allowing the bacteria to adapt to salt-affected soils. The transcriptome analysis further showed that strain RA can tolerate salt stress by balancing energy metabolism through the reprogramming of biosynthetic pathways. One of the key findings of the study is the role of myo-inositol, a metabolite that accumulates in tomato leaves under salt stress. Myo-inositol is known to influence plant fitness, and in this study, it was observed to promote plant growth when triggered by Bacillus sp. strain RA. Importantly, myo-inositol acts as a selective force in assembling the phyllosphere microbiome, which comprises the microbial community on the aboveground parts of plants[2]. This selective force helps recruit plant-beneficial species and destabilizes bacterial co-occurrence networks in the phyllosphere, while not affecting fungal networks. Additionally, interdomain interactions between bacteria and fungi were strengthened by myo-inositol in response to salt stress. This study expands on previous research that highlights the importance of microbial community composition in ecosystem processes[3]. While earlier studies have shown that changes in microbial communities due to disturbances can directly impact ecosystem processes, this research provides a specific example of how a beneficial bacterium can enhance plant resilience to environmental stress through metabolic adjustments. Furthermore, the study aligns with earlier findings on the role of phyllosphere microbiota in plant health[2]. It underscores the importance of a well-assembled microbial community in the phyllosphere for plant survival and health. By demonstrating how myo-inositol influences the phyllosphere microbiome, the researchers provide a mechanistic understanding of how Bacillus sp. strain RA promotes salt tolerance in tomato plants. In summary, the research conducted by Shandong Normal University provides valuable insights into the genetic and metabolic adaptations of Bacillus sp. strain RA, a halotolerant PGPR, and its role in enhancing tomato plant tolerance to salt stress. The study highlights the importance of myo-inositol in shaping the phyllosphere microbiome and promoting plant growth under stress conditions. This work not only contributes to our understanding of plant-microbe interactions but also offers potential applications in agriculture to mitigate the adverse effects of soil salinity on crop yields.

AgricultureBiotechPlant Science

References

Main Study

1) Halotolerant Bacillus sp. strain RA coordinates myo-inositol metabolism to confer salt tolerance to tomato.

Published 5th July, 2024

https://doi.org/10.1111/jipb.13733


Related Studies

2) A plant genetic network for preventing dysbiosis in the phyllosphere.

https://doi.org/10.1038/s41586-020-2185-0


3) Colloquium paper: resistance, resilience, and redundancy in microbial communities.

https://doi.org/10.1073/pnas.0801925105



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