New Bacteria Boosts Growth of Plants Even in Salty Conditions

Jenn Hoskins
26th August, 2024

New Bacteria Boosts Growth of Plants Even in Salty Conditions

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Ghent University found that Microbacterium strain SRS2 helps plants like Arabidopsis and MicroTom tomato grow better under salt stress
  • SRS2 promotes plant growth by activating the abscisic acid (ABA) pathway, which is crucial for stress responses
  • The study suggests that SRS2 could be a valuable tool for improving crop yields in saline soils, aiding sustainable agriculture
Soil salinity is a significant agricultural problem, reducing plant growth and productivity. This issue is becoming increasingly important as soil salinization affects more agricultural lands worldwide. Plant growth-promoting rhizobacteria (PGPR) have shown promise in supporting plant growth under salt stress conditions. Recent research from Ghent University has highlighted the potential of Microbacterium strain SRS2 to promote growth and induce salt stress resistance in plants like Arabidopsis and MicroTom tomato, offering a potential solution to this problem[1]. Microbacterium strain SRS2 was isolated from the root endosphere of tomato plants and tested for its ability to help plants cope with salt stress. In salt tolerance assays, SRS2 demonstrated robust growth up to medium levels of NaCl, although its growth was inhibited at high salt concentrations. When Arabidopsis and MicroTom tomato plants were inoculated with SRS2, they exhibited increased biomass in various growth substrates, both in the presence and absence of high NaCl concentrations. Whole-genome analysis of SRS2 revealed several genes involved in osmoregulation and reactive oxygen species (ROS) scavenging. These genetic traits could explain the observed growth promotion under salt stress conditions. This finding aligns with previous studies showing that certain bacterial endophytes can facilitate plant growth under stress by mechanisms such as ACC deaminase activity[2]. For instance, Pseudomonas fluorescens and Pseudomonas migulae, which contain ACC deaminase, were shown to significantly promote tomato plant growth even under high salinity stress[2]. Further investigation into the mechanisms by which SRS2 promotes growth under salt stress revealed the involvement of the abscisic acid (ABA) pathway. ABA is a plant hormone that plays a crucial role in stress responses, including salt stress. The study used quantitative reverse transcription PCR (qRT-PCR), promoter::GUS, and mutant analyses to determine whether ABA-dependent or -independent pathways were involved in salt stress tolerance in Arabidopsis. The results showed that the growth-promotion effect of SRS2 was lost in aba1, abi4-102, abi3, and abi5-1 mutant lines under salt stress conditions. This indicates that the ABA pathway is essential for the salt stress resistance conferred by SRS2. Additionally, ABA genes related to salt stress were transiently upregulated in SRS2-inoculated plants compared to controls under salt stress conditions. SRS2-inoculated ABI4::GUS and ABI5::GUS plants also showed slightly more activation compared to uninoculated controls under salt stress conditions. These findings suggest that SRS2 promotes growth under salt stress, possibly through the induction of both ABA-dependent and -independent pathways. The findings from Ghent University expand on earlier research by demonstrating that SRS2 can be a valuable tool for enhancing plant growth in saline soils. Previous studies have shown that other PGPRs, such as Bacillus oryzicola YC7007, can also enhance plant tolerance to salt stress via different mechanisms, such as the SOS1-dependent salt signaling pathway[3]. Together, these studies highlight the potential of various PGPRs to mitigate the adverse effects of soil salinity on plant growth and productivity. In summary, the research on Microbacterium strain SRS2 provides compelling evidence that this PGPR can promote plant growth and induce salt stress resistance via the ABA pathway. This discovery offers a promising strategy for improving crop yields on saline soils, contributing to sustainable agriculture and food security.

AgricultureBiochemPlant Science

References

Main Study

1) A novel Microbacterium strain SRS2 promotes the growth of Arabidopsis and MicroTom (S. lycopersicum) under normal and salt stress conditions.

Published 25th August, 2024

https://doi.org/10.1007/s00425-024-04510-2

Related Studies

2) Amelioration of high salinity stress damage by plant growth-promoting bacterial endophytes that contain ACC deaminase.

https://doi.org/10.1016/j.plaphy.2014.04.003

3) Plant-Growth Promoting Bacillus oryzicola YC7007 Modulates Stress-Response Gene Expression and Provides Protection From Salt Stress.

https://doi.org/10.3389/fpls.2019.01646


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