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Abscisic Acid Metabolizing Rhodococcus sp. Counteracts Phytopathogenic Effects of Abscisic Acid Producing Botrytis sp. on Sunflower Seedlings

Summary

Researchers discovered that a beneficial soil bacterium (Rhodococcus sp.) can protect sunflower plants from a harmful fungus (Botrytis sp.) by breaking down a plant stress hormone (ABA) that the fungus produces to weaken plant defenses. Unlike other protection methods that kill the fungus or boost immune responses, this bacterium works by removing the fungus’s chemical weapon. This discovery suggests new ways to protect crops from diseases.

Background

Plant growth-promoting rhizobacteria (PGPR) provide biocontrol of phytopathogens through various mechanisms. Some phytopathogenic fungi produce abscisic acid (ABA) which suppresses plant defense responses. Certain PGPR can metabolize ABA, but their role in plant-microbe interactions remains unclear.

Objective

To investigate whether ABA-metabolizing rhizobacterium Rhodococcus sp. P1Y can counteract the negative effects of ABA-producing necrotrophic fungus Botrytis sp. BA3 on sunflower seedlings through ABA metabolism rather than direct antagonism.

Results

Rhodococcus sp. P1Y showed no antifungal activity but actively metabolized ABA produced by Botrytis sp. BA3. Inoculation with BA3 increased root ABA and inhibited plant growth. Strain P1Y eliminated these negative effects by reducing ABA concentrations and restoring plant growth. Both microorganisms significantly modulated plant hormone profiles including IAA, SA, JA, GA3, and cytokinins.

Conclusion

Rhodococcus sp. P1Y provides biocontrol against ABA-producing Botrytis sp. through ABA metabolism rather than direct antagonism, representing a novel biocontrol mechanism by PGPR that expands understanding of plant-microbe interactions in pathogen suppression.
  • Published in:Plants (Basel),
  • Study Type:Experimental Study,
  • Source: PMID: 40805791, doi: 10.3390/plants14152442
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