The Bacillus cereus Strain EC9 Primes the Plant Immune System for Superior Biocontrol of Fusarium oxysporum

Kenneth Madriz-Ordeñana*, Sercan Pazarlar, Hans Jørgen Lyngs Jørgensen, Tue Kjærgaard Nielsen, Yingqi Zhang, Kai Lønne Nielsen, Lars Hestbjerg Hansen, Hans Thordal-Christensen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

17 Citations (Scopus)
43 Downloads (Pure)

Abstract

Antibiosis is a key feature widely exploited to develop biofungicides based on the ability of biological control agents (BCAs) to produce fungitoxic compounds. A less recognised attribute of plant-associated beneficial microorganisms is their ability to stimulate the plant immune system, which may provide long-term, systemic self-protection against different types of pathogens. By using conventional antifungal in vitro screening coupled with in planta assays, we found antifungal and non-antifungal Bacillus strains that protected the ornamental plant Kalanchoe against the soil-borne pathogen Fusarium oxysporum in experimental and commercial production settings. Further examination of one antifungal and one non-antifungal strain indicated that high protection efficacy in planta did not correlate with antifungal activity in vitro. Whole-genome sequencing showed that the non-antifungal strain EC9 lacked the biosynthetic gene clusters associated with typical antimi-crobial compounds. Instead, this bacterium triggers the expression of marker genes for the jasmonic and salicylic acid defence pathways, but only after pathogen challenge, indicating that this strain may protect Kalanchoe plants by priming immunity. We suggest that the stimulation of the plant immune system is a promising mode of action of BCAs for the development of novel biological crop protection products.

Original languageEnglish
Article number687
JournalPlants
Volume11
Issue number5
Number of pages19
ISSN2223-7747
DOIs
Publication statusPublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords

  • Antimicrobial secondary metabolites
  • Biological control agents
  • Defence priming
  • Induced resistance
  • Kalanchoe blossfeldiana

Cite this